The SFA has written to all member clubs asking them to declare any payments made outside registered contracts in the past decade.
The letter to the 93 member clubs asks them to confirm they complied with the SFA rules by April 6. The SPL’s inquiry into alleged undisclosed payments by Rangers from 1998 is ongoing.
Former Rangers owner Sir David Murray has categorically denied the existence of second contracts hidden from the football authorities but the club are awaiting the outcome of a potential £49million tax case over their use of Employee Benefit Trusts from 2001 to 2010.
Meanwhile, SFA chief executive Stewart Regan has revealed they are considering a revised process to ensure new owners of clubs are ‘fit and proper’.
He said: “We rely on the clubs telling us that the articles have been complied with. People are coming into football, a multi-million pound business, and football needs to look at what could be done differently.”