Cyclist caught riding on Sydney Harbour Bridge

Dramatic dascham vision has captured the moment a cyclist dangerously swerves across a highway exit ramp after crossing the Sydney Harbour Bridge.

9NEWS has obtained vision of the cyclist risking his life at about 2.30am this morning, prompting one concerned motorist to pull over and have a word with him.

The footage starts with the man riding across the harbour bridge, where bicycles are strictly not allowed.

WATCH the cyclist put his life on the line in the video above

The man then makes his way up the Warringah Freeway, before making the snap decision to dart across the exit ramp heading toward Military Rd.

The motorist recording the footage managed to stop the cyclist during his trip.

"You'll get yourself killed, you're not allowed to ride here," the motorist said.

Police later caught up with the cyclist in Neutral Bay, where he was issued a warning.