Premier Rugby have confirmed they are to make a formal complaint to the IRB following comments made by the South African Rugby Union.
Premier Rugby and the SARU have clashed over the availability of Bath's South African fly-half Butch James for Saturday's friendly against Wales at the Millennium Stadium.
James was initially selected for the Test, only for the player to be withdrawn as the match falls outside the IRB's window for player release.
The Springboks, though, have reacted angrily to the decision - with Premier Rugby "alleging a breach of international regulations by SARU through their actions and statements this week".
A statement from Premier Rugby read: "These actions and statements have been repeatedly directed against Bath Rugby and Premier Rugby and seem to have been designed to put unfair pressure on the player and his club, who have acted in accordance with the IRB's regulations and to deflect attention away from the real causes of the issue.
"June matches in the international calendar are played in the southern hemisphere and the schedule is settled years in advance.
"Apparently this extra one-off match outside the schedule and in the northern hemisphere was only arranged earlier this year and seems to be primarily a money-making exercise for which SARU is apparently receiving a large fee.
"When arranging a match outside the international window, all Unions should be aware of their regulations concerning player release. On Wednesday, it became clear that SARU had not properly understood these regulations.
"As a result, actions have been taken and statements made by SARU which have been damaging to the interests of the player, his club and Premier Rugby."