Christmas temporary workers are being urged to take action against "Scrooge" bosses who do not pay enough.
Some bosses do not pay the minimum wage to Christmas staff
The call comes after National Minimum Wage enforcement teams recovered more than £3.2m in unpaid wages for 25,314 workers for 2005-06.
HM Revenues & Customs said many temporary and part-time workers taken on for Christmas do not get the minimum wage of £5.35 an hour for over-22s.
Those affected are urged to call the National Minimum Wage helpline.
Employment Minister Jim Fitzpatrick said: "If anyone thinks they are the victim of Scrooge bosses this Christmas call the National Minimum Wage helpline or complain online, and we will investigate and where possible recover any unpaid wages that may be due."
Paymaster general Dawn Primarolo added that employers and employees needed to remember that anyone working on a temporary or part-time basis over Christmas ""is still entitled to be paid at least the minimum wage".
The workers who successfully claimed money back included a kitchen porter from Leicester who won £5,446 after working at an upmarket restaurant. He had received a fixed rate, regardless of his hours, and had not received a pay rise in five years.
In another case, 180 employees at a packing and distribution firm near London shared £106,403 after asking for help.
The TUC said that rogue employers should be named and shamed if they are caught paying workers below the minimum wage.
TUC General Secretary Brendan Barber said there should be no hiding place for mean bosses.
"Some employers are prepared to take the risk to rip staff off, to cheat them out of the basic entitlement that the minimum wage is meant to guarantee," he said.
"And I hope employers will get the message. You are not going to get away with that kind of unscrupulous, exploitative behaviour."