Hundreds of people have been evacuated and an exclusion zone is in place after an excavator hit a gas line near the Sydney Opera House on Tuesday afternoon.

Firefighters arrived on the scene shortly before 3pm following reports of the incident, and evacuated about 500 people from the Opera House forecourt terrace area and adjoining restaurants as a precaution, a spokesman for Fire and Rescue NSW said.

Around 500 people have been evacuated from the Sydney Opera House due to a gas leak. Credit:Nine News

A 100-metre exclusion zone is in place to the north and south of the damaged gas line and Macquarie Street is closed at Bridge Street.

The gas company is currently working to clamp the line, the spokesman said.