SYDNEY (AFP) - Australian World Cup back Julian Huxley has been diagnosed with a brain tumour while undergoing scans following a head knock during a weekend match, his club the ACT Brumbies said Tuesday.

Huxley, 28, was shocked when doctors broke the news to him Monday following routine MRI scans carried out after he was concussed as he attempted a head-on tackle during a match against the Queensland Reds in Canberra on Saturday.

"The tumour, at the top of his brain, is believed to be benign. The 28-year-old has been referred to a neurosurgeon for further investigation and management," the Brumbies said in a statement.

The Wallabies utility convulsed on the field on Saturday before being taken to a Canberra hospital where he remained overnight for observation.

The next day he had recovered well, showed no ill-effects of the concussion and was cleared of any structural or muscular damage, the club said.

But Huxley was stunned the following day when doctors told him what the precautionary MRI scans had revealed.

"It was a huge shock when the doctor told me I have a tumour," he said. "It's obviously been with me for some time and I've never felt any sort of illness.

"The challenge for me now is to get on with gathering the best advice from the specialists and neurosurgeons, dealing with it and recovering as quickly as I can," he said in a statement.

Brumbies chief executive Andrew Fagan said that the tumour had likely been present for several years and that it was unclear if or when Huxley would play again.

"The news has shaken all of us at Brumbies Rugby," Fagan said. "He is a great bloke and an important member of the team and the Canberra community.

"Our thoughts and prayers are with Julian and his family and we look forward to his full recovery."