Construction Industry Joint Council meet to discuss new deal to start in July.
Pay talks over union demands for a hike in wages for 600,000 craft and civil engineering workers begin today.
Union leaders from Ucatt, T&G and the GMB have put in an initial claim for a "substantial" increase in the basic hourly rate for workers, understood to be a rise from £9 to £15 over the next two years.
The unions are in talks with representatives from the Construction Confederation under the umbrella body the Construction Industry Joint Council over the claim. The current pay deal expires in June.
Other union demands include a cut in the working week to 37 hours, two extra days holiday a year, sick pay improvements and a review of bonuses.
The talks come as civil engineering workers on the Terminal 5 project are on strike over bonus pay arrangements.