"Sixteen Leiria players opted for collective resignation because of salary delays," the union wrote in a statement late on Friday.
"Given the decision, Sunday's match with Feirense will not take place".
Bottom-of-the-table Leiria could be punished with automatic relegation if they miss the match as well as being given the defeat and a fine.
Leiria's troubles may impact on the title race since they are scheduled to play second-placed Benfica, who are four points behind Porto, next weekend.
Outgoing Leiria president Joao Bartolomeu said he could not understand the players' behaviour and that his club should quit professional football.
"If it was up to me we would abandon professional football, that is my opinion. But I have to listen to other club administrators," Bartolomeu said in televised remarks.
"We had the problem solved but the players did not want a deal. We had conditions to pay the three-months salaries in fault," he said.
Portugal's Professional Football League expressed its concern about the situation.
"Portugal is going through moments of severe economic and financial difficulties and professional football is no exception to that," the LPFP wrote in a statement.
"We regret the salary delays," the league said.