The Rugby Players' Association has demanded clarity over reports that investigations into salary cap breaches have been dropped.
The Times reported on Wednesday that England's leading clubs voted in February to suspend investigations into possible salary cap breaches to protect the image of the Aviva Premiership.
Saracens and one other club were reportedly the target of the investigations although Sarries owner Nigel Wray has long denied allegations against the club.
Recommended penalties for breaking the salary cap range from four points for a minor breach to 40 points for a breach over £250,000.
Premiership Rugby have insisted no amnesty is in place and confidentiality arrangements prevent disclosure of any ongoing investigation.
But RPA chief executive Damian Hopley has called for more transparency and accountability.
"Everyone buys into the principle of the salary cap, we recognise its worth and the purpose it is serving for English rugby," Hopley told the Times.
"We've had comments from leading players in the Premiership that breaking the salary cap is akin to being on the field with someone who is taking performance-enhancing supplements.
"It's just not fair. Either you play by the rules or you don't.
"There is a growing sense of frustration amongst the players. We talk about the values of rugby, well there needs to be mutual respect here about what we are all buying into.
"We want transparency and accountability across everything that we do. As the players are held accountable every weekend in front of the viewers and the fans in the grounds, we want to make sure that is the same across the industry."
A Premiership Rugby spokesman has denied the allegations that any investigations or findings could be swept under the carpet.
"We don't make any comment on any salary-cap investigations which might or might not be occurring," a spokesman told Press Association Sport on Wednesday.
"But there is no amnesty in place. The salary-cap system is an integral part of Premiership Rugby and has the support of our clubs."