The number of people receiving unemployment benefits rose by 5,800 in June, according to the latest figures released by the Central Statistics Office.
The increase brings the seasonally adjusted total number of people signing on the Live Register to 444,900.
The Live Register includes people who work part-time, and seasonal and casual workers entitled to Jobseekers Allowance or Jobseekers Benefit.
An additional 1,450 people signed on every week in June, 200 people less than the number who signed on weekly in May.
There were an estimated 41,790 male and 37,447 female casual and part-time workers on the Live Register during the month.
The Central Statistics Office said the standardised unemployment rate in June was 13.4 per cent. This compares with 12.9 per cent in the first quarter of 2010.
Minister for Finance Brian Lenihan said although there continues to be additions to the Live Register, employment growth inevitably follows with some time lag growth in economic activity.
"Of course, unemployment is unacceptably high. But the best way to create and protect jobs is to return to economic growth. Every measure the government has taken over the last two years is aimed at getting those who have lost their jobs back to work."
The Irish Small and Medium Enterprises Association (Isme) said the true level of unemployment was under-reported and is reduced by increasing emigration, increased participation on state training initiatives and a significant rise in individuals staying on in education.
"These horrendous unemployment statistics confirm the fact that any reported economic growth is 'jobless growth' and reflects the reality of what is happening to the labour intensive SME sector, which is clinging on for dear life," according to Isme chief executive Mark Fielding.
An increase of 5,800 in a month shows the weakness in the labour market, with many firms still placing people on short time working or implementing redundancies, said Small Firms Association director Avine McNally.
"It is vital that the Government prioritise the restoration of cost competitiveness to the small business sector; generate confidence in the economy and create the enterprise environment where job losses can be stabilised and created," she added.
Meanwhile, Taoiseach Brian Cowen has said that participation in the Back to Education Allowance scheme doubled this year, with 5,600 of the additional 5,800 who joined the Live Register in June on that scheme.
Fine Gael enterprise spokesman Leo Varadkar said Ireland was in "a lost decade of stagnation" under the current Government.
"Almost 15,000 people joined the Live Register in the last month, or roughly one every two and a half minutes." Mr Varadkar said there could be no recovery with job creation.
"In the real world, a recovery is about having a job to go to and enough money in your pocket," he said. "The Government has fallen into the trap of believing that a jobless recovery is good news for the economy. But a small increase in national output is no good to anyone if it doesn't make any inroads into Ireland's massive unemployment levels," he said.