HMRC said it has found evidence that some professional clubs may not be paying backroom staff the legal minimum wage.

Research has found that posts are being advertised for work at football clubs in areas such as sport science and marketing, as well as match-day roles – such as ball boy supervision, or work as mascots – which appear not to comply with minimum wage rules.

HMRC will initially contact 44 football clubs to ensure that employers are not breaching minimum wage rules.

Michelle Wyer, assistant director of HMRC’s National Minimum Wage team, said: “Paying the national minimum wage is not a choice – it’s the law. It can’t be right that as some players are paid millions of pounds, other members of staff are paid below the legal limit.”

Last year, HMRC enforcement action resulted in 708 employers receiving automatic penalty charges of up to £5,000 and 26,519 employees receiving back pay totalling over £4m, topping up wages that had previously been below the legal minimum rate.

The national minimum wage is £6.19 an hour for workers aged 21 and over. This will increase to £6.31 an hour from 1 October 2013.