Staff at an Outback Jacks in Northbridge were forced to make a citizen’s arrest after a man allegedly threatened them with a knife.

Dramatic CCTV footage shows the restaurant owner and its manager pinning the man to the ground.

The situation escalated when staff confronted the man who they say tried to walk out without paying for his meal.

They pinned the man against a wall after he allegedly threatened to stab them. Eventually, the restaurant’s owner and manager had to sit on the man to restrain him.

“We were sort of expecting him to try again. He had another go trying to get away, that's when we had to bring him to the floor,” restaurant manager Nathan Doncon said.

“At the time you sort of don't think too much about it. It's only afterwards you realise what's actually happened,” restaurant owner Ray Strauss said.

“(We) pretty much told him you can either come in and pay or wait till police get here.”

Police arrived about five minutes after they were called and arrested the 36 year-old man who was allegedly in breach of bail. He has also been charged with stealing and threatening to injure, harm or endanger.

Staff say it was an isolated incident in what had been a crime free period for the restaurant.