Premier Rugby insist they are merely abiding by International Rugby Board rules after Wales head coach Warren Gatland described the situation governing his English-based players' release for World Cup duty as "ridiculous".
Gatland hinted that Wasps back-rower Andy Powell and Sale scrum-half Dwayne Peel could miss out on World Cup selection next year because they will only be available for national duty on August 4, two days before Wales' first warm-up game against England.
The New Zealander said: "The major concern is we have had a letter from Premier Rugby saying players in England will not be released until August 4. That is completely ridiculous to say the players will finish [the season] in May but not be available for national squads until August, two days before we play England in our first warm-up game."
He added: "It's going to limit players playing in England being available in terms of preparation or being available for the squad.
"Picking this squad we have looked at this campaign and the Six Nations, and if a player playing across the (Severn) bridge is unavailable until August 4 it is highly unlikely they will be considered for the World Cup squad."
However, Premier Rugby chief executive Mark McCafferty defended his organisation's position, and told the Daily Telegraph: "This is an International Rugby Board regulation that players only have to be released 35 days before a tournament.
"We didn't lobby for this at all. And no one has said anything about it until this point. It's not an issue for us although it's been characterised as such. It's disappointing when others start to beat the drum and portray us as the bad guys."
Wales players playing in their homeland are available whenever required by the national squad following last year's five-year participation agreement between the Welsh Rugby Union and the four professional regions.
Similarly, England have an eight-year deal in effect between the clubs and the Rugby Football Union, but no such agreement exists for Welsh players employed by English clubs.