A demonstration is today being held at the Uskmouth power station construction site in the long-running row over contracts being awarded to foreign companies.
The mass meeting has been called at the site, near Newport in south Wales, amid complaints that local workers were being denied the chance to apply for jobs.
Local workers have claimed they are being excluded from the scheme, despite high unemployment in the area.
The dispute follows months of strike action across the country after workers complained about the use of overseas labour at the Lindsey oil terminal in North Lincolnshire.
Text messages have been sent to workers across the country urging them to attend today’s demonstration.
On Friday, members of the GMB union voted heavily in favour of industrial action in the long-running row after the union balloted workers at seven sites - BP in Grangemouth; Ineos in Grangemouth; Sellafield; Shell UK Stanlow; Staythorpe RWE in Nottinghamshire; Chevron at Pembroke and Aberthaw in South Glamorgan.