Temp agency staff are failing to receive equal pay in the UK, trade unions have warned.
The TUC is complaining to the European Commission, claiming that agency workers who have worked with a company for more than 12 weeks should be entitled to the same pay as permanent staff. Agency workers can be found in the healthcare, education and hospitality sectors.
General secretary Frances O'Grady said: "The recent agency worker regulations have improved working conditions for many agency workers without causing job losses.
"However, the regulations are being undermined by a growing number of employers who are putting staff on contracts that deny them equal pay.
"Most people would be appalled if the person working next to them was paid more for doing the same job, and yet agency workers on these contracts can still be treated unfairly.
“The government should ignore the inevitable bleating from business that will follow the TUC’s complaint and finally do something to help ordinary workers.”
The row over agency staff pay comes after concerns were sparked about the rise of controversial 'zero-hour contracts'. The flexible arrangement means that staff are tied to an employer and get no guaranteed hours of work or benefits.
The Department for Business said it worked with employers to ensure fair compliance to regulations for agency workers' pay.
"We worked closely with both employers and employee organisations to successfully implement the Agency Workers Regulations," a spokesperson said.
"We will of course consider carefully any information the TUC presents to the European Commission."
Kevin Green, chief executive of the Recruitment and Employment Confederation, said that agency workers had been consulted upon and the legislation was "legitimate".
"Agency workers have benefited since these rules came in. There are lots of things our members were unhappy with in these regulations, there was clearly a compromise made.
"The key thing is to get people into work, to make sure you're creating jobs, if you start unpicking regulations because you decide you don't like them, then you risk creating uncertainty, undermining employers confidence and end up with fewer people in work."