Irish trade unions are planning strikes at various industries next Monday which could also halt flights for hours at the three main airports, unions said on Monday.

The umbrella group Irish Congress of Trade Unions (ICTU) is planning a work stoppage on March 30 in sectors where employers were refusing to pay out wage increases agreed in a national deal last September.

Some employers, including the government, have refused to award pay rises as Ireland is now facing its worst recession on record as well as the highest budget deficit projected in the euro zone due to dwindling tax revenues.

Affected unions were this Monday notifying employers of their plans under a rule to give seven days' notice of industrial action, an ICTU spokesman said.

"The ballot only concerned those people where there was a dispute with their employer over the wage agreement," the spokesman said. "That was in some elements of the private sector and all of the public sector."

An ICTU leadership meeting on Wednesday could still decide to cancel the strike if employers seem ready for compromise, the spokesman said. ICTU later issued a statement saying a "substantial number" of employers had agreed to pay.

The Dublin Airport Authority, which also operates the airports at Shannon in the west and Cork in the south of Ireland, said the SIPTU union was planning a work stoppage between 0400 and 1200 GMT as part of ICTU's action next Monday.

Other unions are also planning to join the action which SIPTU said would effectively shut down traffic at the airports.

Employers group IBEC said it was ready for talks with unions but the original pay deal had become obsolete as Ireland now faced the prospect of more than half a million unemployed.

"(The strike) sends out a very negative signal at a time when ... our reputation is being questioned right across the globe," IBEC Director General Turlough O'Sullivan said.

A string of scandals surrounding now nationalised Anglo Irish Bank has hurt Ireland's image as an investment destination at a time when the government is trying to raise billions of euros in bond issues to finance the deficit.

The 45,000-member Technical Engineering and Electrical Union said it was one of the groups serving notice of a strike but it could still review its position.

"A week is a lifetime in industrial relations," TEEU General Secretary Designate Eamon Devoy told public radio RTE.

IMPACT, Ireland's largest public sector union, said 65 percent of its members had voted in favour of joining the strike, but that was just short of the two-thirds majority required. Its leaders will decide on Tuesday how to proceed.

The government is planning to announce further fiscal tightening measures in a mini budget on April 7, the second emergency budget since October.

A move by Prime Minister Brian Cowen earlier this year to make 2 billion euros of savings despite failing to get agreement from unions has already prompted a series of protests including an unusually large one of about 100,000 people last month.