Watch: Dramatic video shows firefighters at the scene of SkyCity convention centre blaze

Dramatic footage shows firefighters attempting to extinguish a major blaze on the roof of the SkyCity convention centre in Auckland's CBD.

The fire has engulfed the city in thick, billowing black smoke. 

Newshub understands that a blow torch, allegedly left unattended by a worker, started the blaze.

The fire is still uncontrolled. Assistant area manager for Fire and Emergency NZ (FENZ), Dave Woon, said the blaze is proving "very challenging" to extinguish.

A SkyCity spokesperson confirmed that everyone has been evacuated from the convention centre and there have been no reported injuries.

"We are working closely with Fletcher's and the Fire Service to gather as much information as possible, we do not know the source of the fire at this stage," they told Newshub.

It is thought Auckland's gale force winds could present more problems for the firefighters as they continue to battle the flames.

One person is said to be unaccounted for, but Woon says FENZ is not overly concerned at this point.

FENZ said more than 20 firetrucks are at the scene, including one "aerial appliance" from Hamilton.

Auckland Transport is stressing that people should avoid the area. Multiple roads around the scene have been closed.

Watch the video above.

Newshub.