A man going for a walk through the Sydney Harbour Tunnel briefly slowed Friday night peak-hour traffic to a crawl.


About 5:30 authorities were alerted to a man walking through the Domain Tunnel. It took about 15 minutes for him to be apprehended by local authorities.


The man is believed to have been under the influence of drugs. An ambulance was called to the scene but did not take him away. He is now understood to be talking to police.


All northbound lanes in the tunnel were closed and motorists were diverted to the Cahill Expressway.


By 6.30 pm traffic remained heavy but was back to normal levels for a Friday night.