Toulon owner Mourad Boudjellal has suggested Leigh Halfpenny will not be paid by the club if he tours New Zealand with Wales in June.
The full-back has not played for his French club this season after suffering a serious knee injury in Wales' match against Italy in September 2015.
"I'm not paying anyone who's not here in June," Boudjellal said.
Under World Rugby rules, Toulon would be obliged to release Halfpenny if selected by Wales.
Wales coach Warren Gatland names his tour squad on Tuesday, 10 May.
The French Top 14 final will be played on 24 June, the eve of Wales' third and final Test against the All Blacks in Dunedin.
France are expected to tour Argentina without players involved in the French play-off system, which continues during the international window.
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World Rugby's article nine states that clubs have to release players during official international periods, with several of Toulon's South Africans also possible absentees.
"We'll go to all the tribunals in the world, but anyone who's not playing for us won't be paid by the club," Boudjellal added.
"I'm not stopping anyone leaving because there is article nine - but anyone who leaves us before our final match won't be paid by the club."
Halfpenny had been scheduled to return in mid-April and was registered in Toulon's European Champions Cup squad.
The 27-year-old may be fit by the time of the Wales tour and the French play-offs.
"After the episode of the World Cup and the episode of the injuries, the third episode that is about to happen is the [fixture] calendar," warned Boudjellal.
"We could find ourselves in June without three or four players at least because they are going to play friendly matches for their federations.
"I hope the federations have the intelligence to see that in a World Cup year, they'll say to themselves that the Top 14 is a real competition and you have to respect the clubs who look after the players all year."
Toulon lie third in the French Top 14 with three rounds of the regular season still to play.