Andy Murray has said the uncertainty over Novak Djokovic’s situation ahead of the Australian Open is “really bad” for tennis and has left players in shock ahead of the tournament.

Djokovic has been held in a hotel since Thursday after Australian border force revoked the world No. 1’s visa over his medical exemption for a Covid-19 vaccination.

The Serbian, who is being held in a hotel used to accommodate asylum seekers, is challenging the decision and his case will be heard at 10am on Monday local time (11pm Sunday GMT).

Documents issued by Djokovic’s lawyers revealed that the 34-year-old had previously been granted a medical exemption on the basis of recording a positive PCR test on 16 December.

Murray, a long-time friend of Djokovic, said he had not spoken to the nine-time Australian Open champion, who is looking to eclipse Roger Federer and Rafa Nadal with his 21st grand slam title in Melbourne this month, but expressed concern for the Serbian.

“I think everyone is shocked by it to be honest,” Murray told reporters in Melbourne. “I’m going to say two things on it just now. The first thing is that I hope that Novak is OK. I know him well, and I’ve always had a good relationship with him and I hope that he’s OK.

“It’s really not good for tennis at all, and I don’t think it’s good for anyone involved.”

The Briton, who has been handed a wildcard for the Australian Open main draw, said he would wait until the full facts of the situation were clear before commenting futher on the issue.

Other players, such as Nadal, have criticised Djokovic for not receiving the Covid-19 vaccine before the tournament. Australian Open tournament director Craig Tilley said in December that players must have received a vaccine or have a medical exemption in order to compete.

Djokovic, who has publicly criticised mandatory vaccines, has refused to disclose his vaccination status.