Heavy traffic is forming on the Sydney Harbour Bridge this afternoon after an earlier motorcycle crash in North Sydney.
The tunnel has been closed for over two hours now, with all southbound lanes closed.
Traffic is being diverted onto the bridge, but it is heavy back to the Lane Cove Tunnel.
Motorists are advised to use Victoria Road instead.
The motorcyclist involved in the crash was reportedly involved in a police pursuit, and is in a critical condition in hospital.
The rider is believed to have struck a vehicle from behind.
Southbound lanes will be closed until at least 8pm this evening.