An SPL sub-committee met on Wednesday after players' union PFA Scotland submitted a formal complaint on behalf of Hearts' first-team squad on December 16, when wages were not paid on time for a third consecutive month.
December's pay remains outstanding and the SPL have made a series of demands in order to halt the financial uncertainty surrounding the club.
An SPL statement read: "An SPL board sub-committee today [Wednesday] adjudicated in the dispute between 14 players and Heart of Midlothian FC.
"The SPL board sub-committee has ordered December wages to be paid by January 11.
"Interest on all sums overdue from October, November and December wages must also be paid by January 11. January salaries must be paid on time on January 16.
"The club must also pay the claimants' legal expenses and the SPL's costs of today's [Wednesday's] hearing. Both sides have the right to appeal the decision to the Scottish FA within seven days."