Golfer Tiger Woods was found "asleep at the wheel" with the engine running when he was arrested, US media reports say.

Woods was found behind the wheel of his Mercedes, which was stopped in the road, and had to be woken by the arresting officer early on Monday.

"Woods had extremely slow and slurred speech", a copy of the police report published by US outlets said. He was "cooperative" but "confused", it said.

However, the golfer maintains alcohol was "not involved" in the incident.

Woods initially told the arresting officer he was coming back from LA, having been golfing, and said he did not know where he was. He then changed his story about where he was coming from and going to, the police report said.

Officers also recorded that Woods failed some of the roadside tests - such as standing on one leg.

But his breathalyser results showed he "blew zeroes" - indicating a lack of alcohol in his breath.

The player, who was charged with Driving Under the Influence (DUI), blamed "an unexpected reaction to prescribed medication".

"I understand the severity of what I did and I take full responsibility for my actions," he said.

"I want the public to know that alcohol was not involved. What happened was an unexpected reaction to prescribed medications," Woods said in a statement.

"I didn't realise the mix of medications had affected me so strongly." 

Police released a mugshot of Woods, looking unshaven and unkempt, following his arrest in the town of Jupiter.