Scotland's governing bodies should intervene in the Hearts players' wages impasse, according to The Professional Footballers' Association Scotland.
The Scottish Premier League and Scottish FA will not do so unless the players make a formal complaint.
"There is a growing anger and a feeling of isolation amongst the players," said PFA chief executive Fraser Wishart.
"Our members ask for the governing bodies to intervene and help resolve this matter."
At least two of the Hearts first-team squad have recently held talks with PFA Scotland regarding their own situation at Tynecastle.
And four senior Hearts players have been offered contract extensions in the past few weeks despite not receiving their November monthly salaries.
The PFA says it expects Hearts to honour their players' contracts.
"The expectation is that our members simply continue to turn up for training and games as normal without any sign of being paid," said Wishart.
"The governing bodies have an obligation to the integrity of the game in this country and it is imperative that from this aspect our members are paid.
"The players have been exemplary in their professionalism. The current situation, however, is unacceptable and cannot continue.
"Players sign standard contracts which are registered with the governing bodies.
"As part of this contract players also have to adhere to the registration processes put in place by the governing bodies. The governing bodies also adjudicate upon any disputes and are responsible.
"There is therefore a care of duty to ensure that these very contracts are being honoured.
"Our members have certainly played their part; they would welcome support from elsewhere within the game."
Wishart insists that the PFA Scotland would like to avoid litigation to resolve the problems at Hearts, but want reassurances from the Edinburgh club that the situation will be rectified soon.
"Our members wish is quite simple; they want to be paid their wages," said Wishart.
"There is no wish to take legal action against the club and we agree that it is in everyone's interest that Hearts get to January and raise revenue by selling players.
"The longer our members go without pay the more likely that many will look to use the terms of their contract and the Fifa regulations - the club is in clear breach of our members' contracts and players are now looking at their contractual position."
The SPL said it had not received a complaint from the Hearts players.
"Under the standard SPL player's contract, the SPL has the power to adjudicate on any complaint made by a player or players," a spokesperson said.
"To date, no such complaint has been received by the SPL in relation to any Heart of Midlothian player.
"Any appeal against an adjudication by the SPL would be heard by the Scottish FA.
"While the SPL and Scottish FA have the utmost sympathy for any player who is not being paid, it would be entirely inappropriate to meet with the players of any football club. To do so risks prejudicing any case that might later be heard."