Leading sports doctor John Mayhew says Hurricanes halfback Piri Weepu should have been immediately pulled from the field after being knocked out in Saturday's Super 14 rugby final.

Weepu was pole-axed nine minutes into the 12-19 loss in Christchurch after attempting a tackle on his Crusaders counterpart, Kevin Senio.

Weepu's head connected with Senio's knee and he was left unconscious on the ground.

But subsequent onfield tests by the Hurricanes doctor Ian Murphy and physiotherapist Glen Muirhead saw a groggy Weepu play on until the 70th minute.

Mayhew, the All Blacks team doctor for 13 years before retiring from the national team in 2004, queried the decision to leave Weepu on the field.

"Get the player off. Assume that his day is over and go on from there. Whether it's a test match or Super 14 final or a rugby league game," he said.

Mayhew said he would not feel confident about diagnosing a player's fitness immediately after an incident.

"In some instances it could be safe when you're knocked out and you could make a full recovery and carry on. But how do you know it was safe to carry on? We worry when someone's knocked out, they're more vulnerable to another blow to the head."

Weepu admitted on Sunday that he did not remember anything of the previous night's game.

He was named in the All Blacks side to face Argentina on June 24, but coach Graham Henry would not comment on whether it was wise to leave Weepu on the field.

Requests to speak to Murphy were yesterday declined by the Wellington Rugby Union. A spokesman said medical staff were not allowed to speak to the media without clearance.

Another medical specialist said it was exceptionally dangerous to carry on playing after a serious head knock.

There was the danger of suffering a brain haemorrhage and it was prudent to put a player under observation.

Brain Injury of New Zealand executive director Harley Pope said the organisation was deeply disturbed by Weepu playing on after apparently being concussed.

"If indeed Weepu was concussed - and reports that he can't remember the rest of the game would seem to confirm it - we would be appalled that he was allowed to take any further part in the game," he said. "The great danger is that he could easily have suffered a second concussion with very serious consequences not just for a game but for life."