Cape Town - The contractual dispute between the Lions and Gloucester over the services of Franco Mostert has been escalated to World Rugby. 

According to Rapport, SA Rugby and the Lions laid a joint complaint to World Rugby, believing that there were irregularities in the 27-year-old's deal to join former coach Johan Ackermann's side.

The article in the Afrikaans newspaper details that Mostert's agent had begun negotiating with Gloucester while he was still under contract at the Lions.

There was also no clearance certificate from SA Rugby or the Lions.

Without that clearance, which could cost Gloucester around R1.9 million, Mostert will not be able to play. 

The club also faces the possibility of a fine. 

Lions CEO Rudolf Straeuli and SA Rugby declined to comment.

Mostert, who started for the Boks in Saturday's win over the French, has 27 Test caps to his name.