The number of people claiming jobseekers' benefit and assistance increased by 900 in November, after the previous month's figures had showed the first decline in two years.
The CSO said the rise brought the seasonally adjusted Live Register total from 422,500 in October to 423,400 last month.
In November the number of men signing on the Live Register rose by 1,700 while the number of women decreased by 900.
During the year to November there was an unadjusted increase of 146,316 people on the Live Register, a rise of 54.8 per cent. This compares with an unadjusted increase of 161,727 people, or 64.5 per cent, in the year to October 2009.
The average net weekly increase in the seasonally adjusted series in November was 225, which compares with a weekly decrease of 600 in the previous month.
In the month, the estimated number of casual and part-time workers on the Live Register was 39,322 men and 34,308 women.
Despite last month’s rise the standardised unemployment rate remains unchanged at 12.5 per cent in November, compared with 11.6 per cent in the second quarter of the year, according to the CSO.
The Live Register is not designed to measure unemployment. It includes part-time workers (those who work up to three days a week), as well as seasonal and casual workers entitled to jobseeker's benefit or allowance.
Unemployment is measured by the Quarterly National Household Survey and the latest seasonally adjusted figure, for April to June 2009, was that 259,500 people were unemployed.
In response to the figures, Isme, the Irish Small and Medium Enterprises Association, called on the Government to introduce measures in the upcoming Budget to address what it said was a “dire” unemployment situation.
Isme said that unless affirmative action was taken, the country would face “a protracted period of high unemployment, with significant damage to the economy”. Chief executive Mark Fielding said: “Is it too much to ask our Government to take these figures seriously and stand up to the greedy public sector unions who seem hell bent on bankrupting the country?
“The disastrous unemployment figures confirm the continuing haemorrhaging of private sector jobs, while the public sector are allowed to maintain their undeserved, elevated and cosseted status.”
Mr Fielding called for “concrete policies” to prioritise employment maintenance and job creation, including a reduction in employers’ PRSI.
He said a PRSI exemption should be introduced for employers who employ individuals who have been out of work for more than six months and that this should last for two years for each employee recruited.
He said the surplus of €200 million currently in the national training fund should be released to businesses to allow them to upskill existing staff.
Construction Industry Federation (CIF) director general Tom Parlon cuts in nominal levels of current spending designed to stabilise the public finances would be “undermined by further job losses, reduced tax receipts and increased social welfare arising from the cancellation or postponement of construction projects”.
“You cannot achieve smart economic growth whilst stopping or cancelling projects required to make this happen,” Mr Parlon said.
“The need for improvements is evident across all public infrastructure headings – primary and post-primary education, the third level and research sectors, healthcare, public and private transportation, next generation broadband, and in the environmental sphere.”
Mr Parlon said a construction worker on the industry’s agreed pay rates contributes €17,000 in taxes each year.
“A construction worker who loses their job costs the Exchequer €18,000 in social welfare payments, and of course his previous tax contributions and spending disappear.
“In addition, the failure to invest in necessary infrastructure damages the country’s future ability to attract inward investment. Clearly, therefore any decision to cut capital investment has implications long after it is made.”