Unemployed construction workers staged a protest outside over the number of foreign workers working at Ferrybridge power station.
More than 100 people protested on Wednesday at the entrance to a new £300m multi-fuel plant which is currently being built.
Bosses from the Unite union said the contractor for the new project , Hitachi Zosen Inova (HZI), had contracted work out to some employers who were not taking on local workers.
Chris Weldon, Unite regional officer, said: “There are over 300 CVs of unemployed local workers who live within 35 miles of the site on a database at Ferrybridge.
“They are ready to work and they have got the skills but they are being overlooked. We are protesting today to demand that workers whether local or not are treated fairly and that means getting the opportunity to apply for work and being treated equally.
“Ferrybridge is an important project for the local economy so it is outrageous that local workers are being excluded.”
HZI bosses said about 80 per cent of the current work force was UK-based and it would continue to work with the unions to “maximize local opportunities”.
A statement from the company said: “We are committed to using local labour and subcontractors where possible. HZI has been working in conjunction with UNITE and GMB unions.
“HZI considers itself to be fully compliant with [current legislation].
“At present, around 80 % of total work force is UK based.
“HZI will continue to work with union officials and with their representatives as well as politicians to maximise the local opportunities available.”
Planning permission to construct a multi-fuel plant at the Ferrybridge ‘C’ Power Station site was granted in October 2011.
The project is also due to create 50 full time jobs.