Embattled former All Black Sione Lauaki's career is hanging on the result of a blood test after he was found semi-conscious in a car that had crashed into a paddock.

Last month, the 28-year-old loose forward had his last warning from the New Zealand Rugby Union after an alcohol-fuelled incident which led to his pleading guilty to assault.

The union fined Lauaki the $4000 maximum under an agreement with the Players' Association and told him and his representatives it would terminate his contract should there be another incident.

Early on Saturday, Lauaki was driving towards Auckland after playing in the Chiefs' 25-25 draw with the Cheetahs in Hamilton when his late-model Ford sports utility vehicle left the road, smashed through a fence and rolled into a paddock south of Huntly about 4.30am.

St John ambulance staff found him semi-conscious in the driver's seat, wearing his seatbelt. Both airbags in the vehicle had activated.

Lauaki was revived and was able to walk to the ambulance unassisted. He was taken to Waikato Hospital with a swollen arm which will be assessed by Chiefs medical staff as the team prepare to face the Hurricanes in Wellington on Saturday.

A blood-alcohol reading taken at the hospital was "well below" the legal limit, according to his agent, Bruce Sharrock.

He added that Lauaki followed the Cheetahs match with a meal and a couple of drinks with teammates and was heading north to be with his family, who live in Auckland, when the accident happened.

Chiefs spokeswoman Erin Andersen said alcohol was not a factor in the crash.

But Waikato police spokesman Andrew McAlley said police were awaiting blood-test results to determine if any charges would be brought. It was expected to be several days before they were received.

Huntly tow-truck driver Craig Peden told the Herald that the damage to Lauaki's vehicle was substantial.

"I can usually smell alcohol in a vehicle but there was no sign of it," he said. "He must have just nodded off - he would have been tired after his game."

Lauaki played his first test in 2005 and made the last of 17 All Black appearances in 2008.

Ill-discipline off the field has plagued Lauaki as much as recent poor form.

He was suspended for two matches after being cited for spear tackling Lions centre Deon van Rensburg during the Chiefs' 72-65 win in Johannesburg on February 20.

Last year, he attended an anger management course after being charged with wilful damage following an incident at an Auckland motel.