The Government is planning to change speed limits and tighten controls on learner motorcyclists in an effort to improve road safety.
Up to 70 per cent of the 32,000 motorcyclists on Irish roads are driving on provisional licences.
The Minister for Transport, Mr Brennan, said he hoped to bring in new regulations governing motorcyclists within a few months.
Speaking on RTÉ Radio 1's Morning Irelandprogramme, he said 45 motorcyclists were killed on Irish roads last year, representing some 20 per cent of all deaths.
"When you consider the motorcyclists only account for 2 per cent of the vehicle population that's horrendous. Seventy per cent of all motorbike riders are not on full licences - in other words they haven't had a day's training," he said.
Mr Brennan said he would "urgently" examine bringing in a requirement that motorcyclists demonstrate they have taken at least 10 days training with a professional instructor before being issued with a provisional licence.
A Government-appointed review group has also presented the minister with a report recommending an overhaul of the State's speed limits.
Mr Brennan said he agreed with many of the recommendations in principle and that he wanted to "tidy up" speed limits so that people had respect for them and understood them.
"I take the view that a lot of people didn't notice speed limit signs until the penalty points system started to bite, because all of a sudden you were looking at losing your licence," he said.
"If we want people to obey speed limits, the speed limits are going to have to be sensible and they are not sensible in a whole lot of places."
Mr Brennan said 70 per cent of the total road network consists of small, single-lane country roads. A 60 mph speed limit was too high on such roads, he said. The Minister will also examine an increase in the limits on some dual carriageways and the possibility of reducing the 30 mph limit to 20 mph near schools.
Also speaking on Morning Ireland, Mr Michael Kirby, president of the Garda Representative Association, saidalthough he welcomed the extension of the points system, it would be hard for gardaí to implement it without new computer technology.
He said he did not see how the Government could bring in any more offences before the system was running.
But Mr Brennan said a contract had been placed for the computerisation of the system, and would be completed by April or May next year.
From today, motorists will be liable for penalty points for seatbelt offences following the latest extension of the penalty points system.
Under the extended legislation, which took effect from midnight, drivers will be liable for a maximum of four penalty points if they do not wear their seatbelt or if they allow a person under 17 to travel unrestrained in a vehicle. This will also apply in the case of children under four who are not suitably restrained.
The Labour Party spokesman on justice, Mr Joe Costello, welcomed the extension of the penalty points system, but questioned whether the government had now abandoned its commitment to setting up a dedicated traffic corps.
"The Gardai already face significant additional obligations arising from the new Intoxicating Liquor Act and the Immigration Act, while the government has abandoned its commitment to recruit an additional 2,000 members," he said.
"It is clear that if the traffic corps is not established additional Garda personnel will be required to operate and administer the points system if it is to have the desired impact of reducing road accidents and road deaths."