A worker was left dangling by his safety harness on the outside of a six-storey building in the heart of Vancouver's Downtown Eastside after he fell from scaffolding while doing work during the middle of the night.

At around 2 a.m. PT, police and rescue crews arrived to find the man hanging off the Regent Hotel, near the corner of Main Street and East Hastings.

Vancouver Fire and Rescue Services crew members rappelled off the roof of the building to reach the man, secure his line, and bring him down safely.

Once on the ground, Vancouver police officers took him into custody.

Sgt. Randy Fincham said the incident appeared suspicious at first.

A man hanging from his safety harness was rescued off a six-storey building in downtown Vancouver early Wednesday morning. (CBC)

"It is odd for somebody to be working at that time of the day," he said.

But police are no longer involved in the incident, and the investigation is now under the jurisdiction of WorkSafeBC, he said.

"My understanding at this point is, was a person doing some work afterhours. Thankfully this person was wearing an industrial safety harness," he said.