Feb. 21 (Bloomberg) -- Tens of thousands of people marched in Dublin today in what labor unions say is the first of a series of demonstrations by workers to protest against government spending cuts and tax increases.

The Irish Congress of Trade Unions described the march as the “first step in a rolling campaign of action.” The Impact labor union, which represents public workers, estimated the number of protesters at 100,000 in an e-mailed statement.

Ireland’s government this month announced it will introduce a pension levy for public workers and cut spending to plug a deepening hole in public finances and stave off a downgrade of the nation’s debt rating. Unions say lower-paid workers are taking the brunt of the cutbacks.

“The government recognizes that the measures which it is taking are difficult and, in some cases, painful,” the office of Prime Minister Brian Cowen said in a statement today. “It is also convinced, however, that they are both necessary and fair.”

Ireland’s economy may shrink by 10 percent between 2008 and 2010, Cowen has said, while European Commission forecasts that the country’s budget deficit will reach 11 percent of gross domestic product this year, almost three times the EU limit.

To contact the reporter on this story: Fergal O’Brien in Dublin at fobrien@bloomberg.net.

Last Updated: February 21, 2009 11:18 EST