Images of two men using a tightrope to walk between sea cliffs at a popular Albany tourist site have outraged police.

Witnesses said two men attempted to cross The Gap in front of a large crowd on Sunday.

The natural attraction features two rock ledges, about 20 metres apart, with a drop of about 30 metres into the ocean below.

In the pictures the two men appeared to be secured to the tightrope with a safety harness.

Witnesses said one man managed to make it across The Gap while the second made two failed attempts at the crossing having slipped off the rope.

They said he did not fall into the water, but managed to climb back to the edge of the cliff.

The two men did not have approval for the stunt from the Department of Parks and Wildlife, which manages the site.

Police only became aware of the incident after images surfaced on social media and officers said they were stunned by such "stupidity".

"If there was any accident, there's no one there like Sea Rescue to save them," Acting Senior Sergeant Spencer Tebbutt said.

"It could have been very bad, it could have ended in death.

"At a place like The Gap the weather changes all the time and it would be very easy to get in trouble at that sort of area."

Police have urged any potential copycats not to attempt to replicate the act.