The Professional Footballers Association has revealed A-League club Newcastle Jets have failed to pay the entire playing staff superannuation and bonuses.

The payments date back to the start of the financial year and are believed to total $100,000.

Recently departed goalkeeper Ante Covic said it left a sour taste in his mouth when he left the club this week to join Swedish club Elfsborg.

Jets owner Con Constantine does not deny the unpaid dues and said they would all be sorted in the near future but PFA chief executive Brendan Schwab said it is not the first time Newcastle have performed this type of practice.

"The thing with the [Newcastle] club is it's a difficult club to deal with," Schwab said yesterday.

"Normally when we have a series of outstanding payments, we have some concerns about the club undergoing some financial problems.

"Unfortunately this club, under its leadership, has a practice of deliberately delaying payments and making payments at a time which most suits it, irrespective of the impact it has on players.

"I think that's why, unfortunately, the club has struggled to create the high-performance environment that's necessary to maintain the elite level of performance."