The Professional Footballers' Association (PFA) has urged players to ask it for advice on any tax management schemes they are offered by financial advisers or they risk receiving a "life-changing" bill in future.
The union's advice comes after the Daily Mirror revealed on Tuesday that Her Majesty's Revenue and Customs (HMRC) is pursuing £250 million in unpaid tax from 129 former players who invested in a tax avoidance scheme marketed by a company called Kingsbridge.
The scheme was one of many set up to exploit government tax breaks for the film industry more than a decade ago, and involved clients borrowing large sums of money to boost their 'investments' and then claiming tax relief on the interest paid on the borrowings.
The government has since closed this loophole and several courts have agreed with HMRC that tax should be payable on the interest from those large pots of mainly borrowed money.
A PFA spokesman told PA Sport the union had specifically advised players to avoid the Kingsbridge scheme and had advised its members more generally "on the dangers of tax avoidance for some time."
It has set up a dedicated helpline with HMRC to put members in contact with approved financial advisers.
"Developing a relationship with HMRC has been key, so footballers know exactly where they stand, what is solid, what is sound and what doesn't hold up to promises that are made," the spokesman said.
"There is also an ongoing process in educating our members around tax issues to ensure they are better prepared to question investments which sound too good to be true.
"We warn all footballers in this situation that they could find themselves facing a life-changing bill of tax, interest and penalties from HRMC."
It is understood that more than 100 former players have sought the PFA's help in dealing with huge bills resulting from HMRC action against tax avoidance schemes they invested in during their careers.
An HMRC spokesperson told PA Sport: "Tax avoidance doesn't pay. Most schemes simply don't work, and people can end up paying more than they were trying to avoid in their misguided attempts to save money.
"Anyone who anticipates problems paying their tax bill should contact us, as we may be able to offer extra time to pay based on individual circumstances. We have an outstanding record for supporting those facing genuine difficulty."