A n*ked and possibly drug-affected man has been arrested in Sydney’s south-west, after he allegedly jumped into a moving car and caused it to crash, 9News reports.

The man was first spotted clothed and running down Woods Road in Sefton about 1.45pm today, police believe.

9News reports that he had been dropped in the area moments earlier by friends, who continued to circle and watch as the incident unfolded.

Workers at a nearby industrial site said the man wandered in and out of traffic for more than 10 minutes.

He then jumped through the window of a passing car and allegedly assaulted its driver, police have told 9News.

“He started grabbing the driver, bit him on the ear,” one witness said.

The car veered off the road and crashed into a fence, before the man climbed out of the car and stripped off his clothes.

A policewoman was filmed using capsicum spray to arrest the naked man, who is aged in his 30s.

He has been taken to Bankstown Hospital for assessment and will be questioned by police.

The driver and his passenger were also taken to hospital with minor injuries.