The number of people joining the Live Register increased by 5,200 in December, figures from the CSO show, the first increase in four months.
Seasonally-adjusted figures show that there were 440,000 people signing on in December 2010, compared to 438,300 in November and 430,300 in December 2009.
The unemployment rate now stands at 13.4 per cent.
This means that 1,040 signed on each week in December, compared to a weekly fall of 1,050 in November.
September, October and November had seen a steady decline in the number of people in receipt of unemployment benefit.
In absolute terms, the number signing on the Live Register in December was 437,079, 13,484 more than the previous year, and representing an annual increase of 3.2 per cent.
This compares to an annual increase of 11,497 or 2.8 per cent in November.
The number of long term claimants increased by almost 5,000 to 155,000, a jump of 3.3 per cent.
Some 81,000 under-25s were on the Live Register in December, down 3,118 in the year.
Irish nationals accounted for 82.5 per cent (360,434) of the number of people on the Live Register in December. There was a monthly increase of 10,214 (2.9 per cent) in Irish nationals and an increase of 1,863 (2.5 per cent) in non-Irish nationals joining the register.
In terms of regional trends, the largest increase took place in the south-east which saw a jump of 3.9 per cent in people signing on, while the west of the country saw the number of people joining the live register increase by 3.3 per cent. Dublin saw the smallest increase, at 1.6 per cent.
Some 18.8 per cent of those on the Live Register - 82,058 in total - were casual or part-time workers. This compares with 73,999 such workers a year earlier.
Meanwhile, seperate figures from the Department of Enterprise, Trade and Innovation released today show that 2,870 redundancies were officially notified to the Department in December, compared to 4,608 the previous month. The December figures bring the total number of redundancies for the year to 58,731, compared to 77,001 in 2009.
National Irish Bank chief economist Ronnie O'Toole said the increase in the number of part-time workers on the Live Register indicates that firms are turning to part-time working to cut costs.
"The number of people on the Live Register who are part-time workers has grown strongly over the last year as firms cut hours worked to avoid redundancies. The number of casual/part-time workers on the Live Register increased by 8,100 during 2010 representing the majority of the total increase in the Live Register of 13,700," he said.
The director of the Small Firms Association, Avine McNally, said both sets of figures illustrate that the continuing cost of doing business in Ireland for small businesses will have further consequences for the employment prospects of Irish workers.
"The 2010 job figures show that the impact of job losses has been concentrated in the lower skilled occupations. Ireland appears to be experiencing a classical labour market mismatch situation, with significant skill shortages in some areas such as IT and specialist's sales coupled with an oversupply in other occupations. The task the Government faces in re-skilling and retraining is daunting, but necessary, if Ireland is to avoid a long period of structural unemployment."
Describing the figures as "disappointing", Alan McQuaid of Bloxham Stockbrokers said the outlook for employment remains fairly downbeat in the immediate future.
"We are only a week into 2011 and the news of job losses in recent days makes fairly bleak reading. A pick-up in the labour market tends to lag recovery in output/GDP by six to nine months, so it is likely to be the middle of this year at the earliest before there is any real sign of underlying improvement in employment conditions."
He added that further losses in the construction, financial services and retail sectors look inevitable in the short term.
According to the Irish Congress of Trade Unions, the unemployment rate of 13.4 per cent would have been far higher only for the resumption of mass emigration. "The net outflow was around 70,000 to April last and it is expected to be of a similar number for the year to April 2011," the union said.
