An increasing number of top-flight clubs have called for the current level of the cap to be reduced by as much as 25 per cent.
Reports on Monday evening suggested Premiership clubs have unanimously agreed to cut the salary cap by £1million from the 2021-22 season.
The spending limit could reduce from £7m to £6m to help clubs with the losses incurred as a result of the Covid-19 pandemic.
The senior ceiling is set to come down to £5m from the 2021/22 season, plus the existing £600,000 of academy credits, to help clubs with the losses incurred as a result of Covid-19.
The reduction will be in place until the end of the 2023/24 season.
It is hoped the cap could then return to the current level of £6.4m plus £600,000 academy credits.
Changes have also been agreed to the marquee player dispensation, which will remain as two players' salaries not counting towards the cap for the next two seasons before being cut to just one from the 2022/23 season onwards.
Players across the Premiership recently took temporary 25 per cent cuts to help their clubs through the financial difficulty caused by a lack of match action since March.
And RPA chairman Mark Lambert says Premiership Rugby Limited (PRL) have been seeking agreement to cut players' wages by the same amount on a permanent basis.
On Wednesday morning, Lambert issued a strong statement, insisting the RPA will 'continue to fight for our members throughout this crisis'.
Lambert said: “Most of the players have already had temporary 25 per cent pay cuts since March and April as a result of the unprecedented financial challenges exposed by Covid-19.
"PRL have been seeking agreement to reduce players’ wages permanently by 25 per cent across all PRL clubs. This was unanimously rejected by the Players’ Board.
"The RPA have been working diligently over the last 12 weeks to seek to avoid a repeat of the damaging situation the game found itself in when the clubs imposed temporary wage cuts on a unilateral basis in mid-March.
"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.
"In the meantime, the RPA position remains unequivocal: the RPA is opposed to permanent cuts for our members.
“From the outset of this crisis there has been an absolute disregard for the players and the values of the game.
"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 June 18.
"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.”
But Harlequins chief executive Laurie Dalrymple gave the perspective of some Premiership clubs.
Dalrymple says the enforced lockdown has laid bare the financial fragility of the sport and feels it is important to introduce a potential reduction as part of a broader re-structuring.
Dalrymple said: "We knew before Covid-19 that financially the structure of rugby is by and large fractured, it's not working.
"There might be one or two clubs who are an exception but virtually all clubs are losing more money than they are bringing in.
"Something has to change, so we would be supportive of how the salary cap could change. I genuinely don't think it should be the only discussion point, but it is a very important one.
"I think it has to be lowered in keeping with what's then going to make the club sustainable, but we have to be cognisant of the fact that when we do get our sport operating commercially, then we have to raise it."
Harlequins, like Saints, furloughed the majority of their staff in the early stages of the lockdown but Dalrymple still estimates the club could finish the year up to 50 per cent down in terms of their projected revenues.
He added: "It's incredibly difficult for us at the moment. We haven't entirely switched off our revenue streams.. but it's a huge amount of pressure on us.
"It's going to take us probably longer than we thought to come through this, and it's going to be a long road ahead to get anywhere near the level of financial and commercial income that we had, on a financial programme that was already fairly fragile before the pandemic."