Temporary workers across the EU could be given greater rights if a historic deal is reached today by ministers in Luxemburg.
Under the arrangement, temporary or agency workers would be given the right to have the same pay and entitlements from the first day of their contract as staff workers.
SIPTU is expected to welcome agreement if it is reached, although it is not yet clear what bearing this would have on its position on the Lisbon Treaty.
The potential deal follows years of wrangling between member states like Britain who prefer to limit the role of the EU in employment law, and other countries like France and Spain that want greater worker protections across Europe.
Ireland supports the compromise put forward by the Slovenian presidency of the EU since it would allow member states to opt out of the parity rule if there is agreement between employers and unions at national level.
Irish officials in Luxemburg say the deal would essentially acknowledge Ireland's social partnership model.
The breakthrough has been brought about by the UK government recently reaching a deal with British unions on temporary workers.
That deal allowed London to lift its opposition to an EU-wide agreement, since it would recognise Britain's right to negotiate on the issue at local level.
There are some 8m temporary workers across the EU. No official figures exist for Ireland, but it is thought that many thousands of temporary workers are employed across a range of industries, especially catering and construction.
There are 520 agencies licensed to employ temporary workers, many of whom come from eastern Europe.
At present, temporary workers legally benefit from minimum wage and health and safety legislation, although SIPTU says there have been numerous breaches and that many foreign workers are effectively under the radar.
Questions about whether temps would be entitled to holiday or sick pay, or overtime, could ultimately be addressed through social partnership talks.
SIPTU has accused the Government of having blocked the EU directive, only lifting its opposition after Britain withdrew its objections.
Irish officials deny this, saying that the Government has simply wanted Ireland's social partnership to be given due recognition.
