SkyCity convention centre fire: Commuters warned to avoid CBD due to gridlocked traffic, smoke inhalation

Motorists are being urged to avoid Auckland's CBD due to gridlocked traffic following the fire at SkyCity's convention centre.

Main roads and motorway on-ramps have been closed following the inferno, which engulfed the city in thick, toxic smoke on Tuesday afternoon. 

Areas of Wellesley Street, Nelson Street and Hobson Street are cordoned off to allow fire engines access to the blaze, which erupted on the roof of the $700 million building at 1:10pm.

Auckland Transport (AT) said Fanshawe Street is closed eastbound between Nelson Street and Hobson Street as of 5:30pm.

"Avoid this area or expect delays and diversions," said AT.

As of 4:50pm, the Cook Street off-ramp, Fanshawe Street off-ramp, Hobson Street off-ramp to State Highway 1 and State Highway 16 and Nelson Street off-ramps into the CBD are now reopened.

Delays and diversions for bus services are also expected. The major Northern Express service is primarily affected by the cordons.

AT staff have been deployed to redirect commuters to temporary bus stops. 

NZ Police urged motorists to delay travel and have warned the public to stay away from the area due to the persisting smoke.

The Auckland Regional Public Health Service has issued a warning to CBD locals to take precautionary measures to avoid smoke inhalation.

"Public health alert... if you live or work in Auckland CBD or surrounding areas, take precautionary measures to prevent breathing in smoke," they tweeted.

Locals have reported a strong smell of burning plastic and chemicals as the smoke continues to engulf the city. 

ARPHS has advised locals to stay away from the fire site and out of the smoke, to keep windows closed, shut down external ventilation and wipe down surfaces used for cooking and food preparation.

"People who smoke, the elderly, children and those with heart disease, asthma or other lung conditions are at greatest risk of harm from smoke inhalation and should avoid exposure," the health service tweeted.

Anyone with shortness of breath or worsening asthma symptoms should see their doctor.