Welsh rugby bosses say there is no room for manoeuvre when it comes to budgets for player contracts.
Possible strike action is one option to be discussed next week by the body representing players in Wales.
Interim WRU chief executive Nigel Walker met with senior members of the Wales squad on Wednesday to "further clarify the current position".
The Professional Rugby Board, which runs the professional game in Wales, says salaries have been too high.
A statement released later on Wednesday said that while higher salaries may be on offer at some French and English clubs, the packages on offer to Welsh players are "in line with the UK market".
The PRB said the average salary of a Welsh professional rugby player under a new, verbally agreed six-year framework would be around £100,000 a year.
A salary cap for the 2024-25 season will be "in line with most competitors", the board says, although the cap for next season, 2023-24, will be higher so that existing contracts are honoured.
However players at Wales' four professional teams - Scarlets, Dragons, Ospreys and Cardiff - insist their complaint is around the uncertainty over their immediate futures.
BBC Wales understands as many as 70 regional players are out of contract at the end of this season.
And with no formal budgets agreed for the coming seasons, contracts discussions remain on hold.
The PRB includes representatives from each of the four regions, plus acting WRU chief executive Nigel Walker, WRU finance director Tim Moss and two independent members, including chairman Malcolm Wall.
'Sustainable footing'
"The new agreement offers a complete funding package to the professional game in Wales, but it does come with financial limitations which will directly affect salary negotiations," said Wall.
"The cold facts are that the WRU and clubs have been paying salaries that their businesses cannot afford, so the new agreement establishes a new framework for contract negotiations.
"There is a stipulation that all current contracts will be honoured, but these businesses must return to a sustainable footing in order for the success we all crave to follow."
The statement added there is "no room for manoeuvre" when it comes to the overall budget available for player contracts.
Acting WRU chief executive Walker had previously said all player contracts were likely to be completed by the end of February.
"We have absolute empathy with the professional players in Wales and are hugely grateful for all they do for our national game, just as our regional sides are for the commitment of their players," Walker said after meeting with the Wales squad.
"We know we are not in an ideal situation, but it is incredibly important for the whole game in Wales for us to get this next step right."
'Mass exodus'
Former Wales captain Sam Warburton warned that the reduction in player salaries would lead to a "mass exodus" of players even if it did make business sense.
In an Instagram post, he said: "If it wasn't for benefactors the pro club game simply wouldn't exist and sadly at this rate, it won't for much longer as things are currently.
"I appreciate players' wages and expectations need to be reset, but not at this level and after agreeing reductions already to get through [the] Covid hangover."
Cardiff captain Josh Turnbull, a representative on the Welsh Rugby Players Association, hit back at claims their protest was only about salaries.
In a social media post he wrote: "This is NOT about what players earn. It's the fact players don't know if they have a job in 4 months time!
"The vulnerable and uncertain situation is causing severe stress and wellbeing issues and this is increasing day by day."
Veteran Ospreys lock Bradley Davies had earlier said strike action would be the "last option" amid the ongoing contracts freeze, with Wales due to host England in the Six Nations a week on Saturday, 25 February.
"None of the boys want that," said the 36-year-old, who won the last of his 66 Wales caps at the 2019 World Cup.
"They want Welsh rugby to get better again, they want this to stop and for us to move forward and to compete with other teams and get better.
"It's not to cause a fuss - it's just that boys are playing Test match rugby and regional rugby and they don't know if they've got a job in four months."
Davies said the players' stance was not primarily about financial gain.
"It's not about the money, we're asking for a voice in the way things are run - like player welfare, how many games you play a season, how much contact, mental health," he added.
"Us as players have got zero input in that at the moment.
"We're expected to rock up for work, run into a brick wall and then take our money at the end of the day and then get up Monday and go again."
Ospreys head coach Toby Booth said players "wouldn't be human" if they were not distracted by the ongoing uncertainty.
He added: "If they feel they have to make a stand, I understand that completely."