A serious knee injury has cruelled Karmichael Hunt’s Rugby World Cup hopes.

Scans have revealed Hunt will be sidelined for 12 weeks with a medial ligament tear suffered in the NSW Waratahs’ Super Rugby loss to the Jaguares in Sydney last Saturday.

The dual international’s lengthy lay-off means he will miss all five of Australia’s Tests before their World Cup opener against Fiji on September 21.

Waratahs coach Daryl Gibson, who handed Hunt a lifeline by signing the 32-year-old this season after he was unwanted at the Queensland Reds, said the injury was a bitter pill for centre to swallow.

“Obviously he’s had a really solid season for us. When he first came down here, there were a lot of questions regarding his off-field (disciplinary record),” Gibson said on Wednesday.

“But he’s certainly answered that in spades. He’s been fantastic for our team, a fantastic leader and he’s had an excellent season for us.”

If all goes well, Hunt will be back ready to play at the end of August, less than a month before the global showpiece kicks off.

“I don’t know where that puts him in the frame for the Wallabies,” Gibson said.

“Obviously he’s going to go through his rehab processes and see where that gets him.”

Hunt played all six of his Tests in 2017 but has so far been overlooked by Wallabies coach Michael Cheika for two training camps this year.

Off contract at the end of 2019, the Waratahs are keen on retaining Hunt.

“We’re certainly having those discussions,” Gibson said.

“Whether we can get to the money that he’s after is another question.”