Lane Cove tunnel fire: Crane engulfed in flames sparking traffic chaos in Sydney

A crane fire in a major Sydney tunnel has halted traffic at the start of morning peak hour.

The mobile crane was on fire in the eastbound tunnel, though both eastbound and westbound vehicles were now being diverted.

Government agency Transport for NSW reported the fire about 6.30am on Thursday.

'Traffic is already heavy, especially towards the city, so motorists are advised to allow plenty of extra travel time,' a government advisory reads.

Transport for NSW spokesman Craig Moran told 2GB motorists should avoid the area.

'There has been a fire involving a mobile crane which has resulted in the Lane Cove Tunnel being closed in both directions,' he said.

'That's purely for safety reasons...of course all the traffic is being diverted up onto Epping Rd.' 

'Our advice for people at this stage if they haven't headed off on their journey yet, if they can avoid that lane cove tunnel area up there up at lane cove that would be fantastic.

'It'll help bring congestion down and they'll probably have a smoother trip.'

A Fire and Rescue NSW spokesman said the internal sprinkler system extinguished the fire.

Four fire trucks were delayed because of the traffic and arrived about 14 minutes after the call came in, he said.

Firefighters donned breathing apparatus but when they arrived at the vehicle the sprinkler 'deluge' system had put out the fire.

The Fire and Rescue NSW spokesman had no information about the cause of the fire, or how many vehicles were stuck in the tunnel behind the fire.

Police would need to make sure anyone who got out of their vehicles was accounted for, the spokesman said, but there were no reported injuries.

The tunnel would be reopened within a couple of hours, which indicated there was little to no damage to the underpass, he said.

More to come.