The Government will make a last-ditch effort today to block an EU law that would give 30,000 temporary workers the right to the same pay and conditions as full-time staff.

The draft Temporary Agency Workers directive would entitle agency workers to the same pay and conditions as full-time staff after a grace period of up to six weeks.

The Government believes the proposed law would undermine Irish competitiveness, as multinationals and some public health authorities depend on temporary workers. It has estimated that if implemented it could lead to a 20 to 30 per cent increase in costs in certain sectors where firms would have to offer pension, holiday and other rights.

But so far the Republic has been unable to garner enough support from EU states to block the directive, which is supported by countries favouring a more social Europe. The UK, Germany and Malta are also opposed to the directive but last night it remained uncertain whether Poland would join the group to form a blocking minority in a vote scheduled for today.

Minister of State for Labour Affairs Billy Kelleher meets his British counterpart John Hutton in Brussels today to discuss strategy ahead of the crucial vote on the new directive. London was also desperately trying to cobble together a coalition of states that could block the directive, which Gordon Brown has warned could end flexible working in the UK.

Portugal, the holder of the rotating EU presidency, has negotiated what it considers a grand compromise by combining a political deal on the temporary agency directive with a deal on the controversial working time directive.

The working time directive aims to limit the amount of time that workers can be forced to work per week but despite several years of negotiation has still not been agreed by member states.

Last year France, Spain, Italy, Greece and Cyprus objected to a deal on the directive that would have enabled the UK to retain an opt-out for its workers from the law. But EU diplomats have signalled that a deal may be possible this time if the temporary agency workers directive can be adopted by member states at the council of ministers.

Trade unions strongly support the directive, which they argue will abolish a two-tier workforce that enables firms to pay temporary staff lower wages for the same work.