The Cabinet has decided that the whole country will move to Level 3 restrictions from midnight on Tuesday for three weeks.
This follows the rejection of a recommendation from public health officials to move to Level 5 to slow the spread of Covid-19.
Speaking at Government Buildings on Monday night, Mr Martin said there had been an exponential increase in the rate of transmission of Covid-19 across the country and that “we all must respond”.
He said we are in a “very different situation” to last March and businesses were beginning to recover while vital health services were backlogged.
Severe restrictions now would have a damaging impact on these and as a result the Government had decided “at this stage” not to move “to a more comprehensive lockdown”, he added.
He said an immediate and more comprehensive lockdown would make it harder to deal with non-Covid health concerns. However, he said it was essential steps be taken to bring down the rate of infection and therefore the country would move to Level 3 of the Government’s Living with Covid Strategy from midnight on Tuesday for three weeks.
This would mean the regulations potentially being eased from midnight on October 27th - just days ahead of Halloween.
Mr Martin said measures would also be stepped up to increase compliance with guidelines.
He said most people were following current guidelines but there was also no doubt “some are taking a more lax attitude”. He said the virus was spreading because people were allowing it to spread.
The Taoiseach said he understood how frustrated people were and that the “yearning for normality grows stronger all the time”. However, he said Covid-19 was “still deadly and we can’t ignore the threat it poses”.
“If we act now we can stop the need to go further,” he said in relation to moving to Level 4 or Level 5.
There would be a time “where we don’t have to worry about carrying or transmitting the virus” but what happens next “rests in our own hands”, he added.
It is understood several Ministers spoke forcibly at a Cabinet meeting on Monday evening about people not taking the advice seriously. It is expected enforcement will include widespread Garda checkpoint in all counties.
Earlier,the coalition party leaders met the chief medical officer Tony Holohan and other members of the National Public Health Emergency Team (NPHET) to discuss its recommendation for an effective national lockdown for four weeks.
At present Dublin and Donegal are on Level 3 restrictions, with additional measures restricting pubs and restaurants to outdoor seating only in the capital. The rest of the country has been on Level 2.
A Government press conference is to be held on Monday night with Minister for Health Stephen Donnelly and other members of the Cabinet.
Earlier a Government source said the manner in which the latest NPHET recommendation was handled was a “bad day” for the effort against the pandemic because it had the effect of setting politicians against doctors in public for the first time.
That public divergence could have been avoided, said the source, if more “hard graft behind the scenes” had been carried out before anything had been made public.
NPHET on Sunday recommended that the whole country be moved to the highest level of restrictions in the Government’s Covid-19 roadmap amid concern over the spread of the disease and rising numbers in hospitals.
In a letter sent by NPHET to Minister for Health Stephen Donnelly on Sunday, seen by The Irish Times, the health body warns of a “significant and deteriorating” epidemiological situation.
“NPHET advises that it is vital to do everything in our power now (‘now’ is underlined in letter) to arrest the current trajectory nationally and suppress the virus back down to a low level of transmission in advance of the winter months.”
Level 5 would see a ban on all household visits and social or family gatherings, and only essential retail shops would be permitted to open. People would be advised to stay at home except for exercise within 5km of their home.
Only 10 people would be permitted to attend funerals and just six people would be allowed at weddings. Unlike the previous lockdown announced last March, schools, creches, and higher education institutions would remain open, with additional protective measures. Pubs, restaurants and cafes would move to offer takeaway services only, with no organised outdoor gatherings or sporting events to take place.
Dr Holohan chaired Sunday’s NPHET meeting, returning to his role as chief medical officer after stepping aside for a period for family reasons.
It is understood he reiterated the rationale behind the recommendation - which took the political system by surprise - at his meeting on Monday with Taoiseach Micheál Martin, Tánaiste Leo Varadkar and Green Party leader Eamon Ryan.
There was consternation in Government circles on Sunday night when news of NPHET’s advice broke, given the social and economic impact of the months of severe restrictions had earlier this year.
Several sources were highly critical of NPHET for the sudden move, which had not been signalled in advance to Government. Two senior sources described the move as “irresponsible” while another senior figures said it was “completely bizarre”.
A meeting of an oversight committee, chaired by the country’s top civil servant Martin Fraser and involving the secretaries general of other relevant departments, was scheduled on Monday to discuss NPHET’s advice. The committee is tasked with considering how public health advice can be applied in practice.
A meeting of the Cabinet sub-committee on Covid-19 was due to take place after this followed by the full Cabinet meeting.
Resistance to the move to Level 5 is strong in Fianna Fáil and Fine Gael, while it is understood that the Green Party leader Eamon Ryan is concerned about any move to Level 5 because of the impact it would have on the economy and society.
Three senior sources said that there needed to be an immediate effort to increase ICU capacity in the system by making arrangements with private hospitals - as was done in the spring, though it was not utilised.
HSE chief executive Paul Reid tweeted on Monday morning that there was obvious concern about Covid-19 trends and figures.
“But we also know the impacts of severe and regular restrictions in society on the public health, wellbeing, mental health and the economy. Level 5 recommendation to Government has to be considered in this context too,” he said.
Minister for Higher Education Simon Harris said he doubted "many of us got a night's sleep" after news of NPHET's recommendation emerged.
“So many worries & questions on people’s minds. Leaks & speculation don’t help. Today needs to bring clarity. Until then let’s focus on what we can control & what we can do - keep distance, reduce contacts, wear face coverings,” he tweeted.
Dr Mary Favier, a former Irish College of General Practitioners president who sits on NPHET, said the “inevitable truth” was a lockdown was needed to protect the country’s vulnerable healthcare system.
“The reality is that if we keep going the way we are, if you or I had a bad road traffic accident in November, or needed emergency cardiac surgery, there might not be an intensive care bed for you or I,” she told RTÉ Morning Ireland.
“GPs are concerned at what this winter is going to look like. It’s not just a fear, it’s a reality,” she said. The healthcare system was already under strain with both Covid and non-Covid cases, the GP said.
Fianna Fáil TD Jim O’Callaghan said the Covid-19 response was a “political question that should be answered by weighing up the current and future threat posed by Covid against the current and future threat posed by the restrictions.”
“We can’t answer that question by only considering Covid,” he tweeted on Monday.
In the past month the five-day average of cases - one key metric tracked by NPHET - has gone from 99 a day to 463.
The national incidence rate of the virus has trebled from 31 cases per 100,000 in 14 days to 108.9 per 100,000. Dublin’s incidence rate has hit 172.8 cases per 100,000, with Donegal seeing 189 cases per 100,000 in the last 14 days.
Another trend that has added to public health officials’ concern is the steady increase in the number of Covid-19 admissions to hospital, and intensive care.
The number of people in hospital with Covid-19 has increased from 40 to 141 in the last month, with 21 patients now in intensive care units.
Prof Anthony Staines, a Dublin City University academic and public health expert, said it was clear "Covid-19 is out of control and is rising across the whole country."
“That’s been clear for some time, but whether we should be starting with Level 5 is a different question,” he told Newstalk Breakfast.
“I think the public is much less concerned about this than some elements within the business community and at least one element within the Cabinet. We’re going to need to do something because the number of cases is rising steadily, the number of admissions is rising steadily.”