Companies that consistently pay their male workers more will be named and shamed under landmark legislation being published today.
The single equality bill, which will also force public bodies to prevent class discrimination, is being presented to the public ahead of a debate and vote in the Commons.
The bill combines all the myriad parts of Britain's equality laws, including several new pieces of legislation.
Public bodies will have an obligation to reduce inequality, for instance by encouraging parents from poor backgrounds to apply to successful local schools.
Private companies will also feel the effects of the bill, with firms being forced to provide audits of their pay to staff, so gender gaps can be spotted.
The scheme also applies to public-sector bodies with 150 employees or more, including Whitehall departments, local councils, strategic health authorities, regional development agencies and the Met as well as ministers.
David Frost, director general of the British Chambers of Commerce, said the government was risked worsening the recession by putting extra regulatory burdens on businesses.
"Last Wednesday the chancellor positioned business at the heart of the economic recovery in the Budget and said all actions were to help reinforce that position," he said.
"Yet within days the government is announcing that businesses are to be burdened with a requirement to carry out gender pay audits in the equalities bill. Clearly some sections of government just don't get it, that business is critical to recovery."
But Brendan Barber, general secretary of the TUC, said audits were the best way to combat pay inequality.
"The UK will never tackle the problem of unequal pay until there are systems in place exposing the huge gap between what men and women doing similar jobs in the same workplaces are paid," he said.
"The business lobby will of course complain loudly about what they see as another burden on business, but pay audits are the very least employers should do if we are to finally get rid of low and unequal pay for female workers in the UK."