England's rugby players are heading towards a "significant legal dispute" with clubs over salary cuts.
On Monday, Premiership clubs voted unanimously to cut the salary cap by £1.4m from the 2021-22 season.
The majority of top-flight players took a 25% pay cut in March because of the financial impact of the coronavirus pandemic.
Players will take legal action unless urgent talks are held on the matter, the Rugby Players' Association says.
Mark Lambert - chairman of the RPA, the players' union - said: "From the outset of this crisis, there has been an absolute disregard for the players and the values of the game.
"The RPA position remains unequivocal: the RPA is opposed to permanent cuts for our members."
Premiership Rugby, which announced last week that the season will provisionally resume on 15 August, had attempted to make the temporary 25% pay cuts permanent in May, a move which was blocked by the Players' Board.
However the RPA was not involved in the latest decision to reduce the salary cap unilaterally, with Lambert criticising the "totally unacceptable" way the clubs are acting with regards to players' contracts and pay.
"This latest situation could have been entirely avoided with a collaborative and transparent approach and we now find ourselves heading towards a significant legal dispute unless meaningful and genuine dialogue takes place urgently," Lambert added.
"Players at some clubs are now being served with ultimatums and being put under undue pressure to sign amended contracts through the manufactured deadline of 18 June.
"To be clear, this is a totally unacceptable way to operate. Players are the lifeblood of the game and should be treated with respect. Players should not engage with this approach. The RPA will continue to fight for our members throughout this crisis."
Speaking to BBC Sport, RPA chief executive Damian Hopley said there was an "absolute concern" about players going abroad if the situation could not be resolved.
"If this starts to impact on the England team and availability, and the exceptional circumstances clause that exists in the professional game agreement between the clubs and the RFU, then we've all got to sit up and take notice," he said.
"So the more simplicity and transparency we can bring to that the better. But there is an absolute concern because as we've said all along, players have very short shelf-lives, they have to optimise their earnings as best they can.
"Japan is emerging as an absolute hot-bed for talent and George Kruis is off there and I'm sure he'll do brilliantly, as are a number of players out there."