The First Division club's players are reportedly considering strike action ahead of tomorrow's game against Partick Thistle.
They only received the final part of their January wages this week and PFA Scotland said today there was "little prospect of payment in full in the immediate future" for this month's wages.
Its head Fraser Wishart said: "Players at that level are not highly paid therefore any delay in payment of wages can lead to hardship, inconvenience and upset."
He said PFA Scotland had complained to the league "for illegal deduction of our members' salary and for breach of contract by the club."