Three injured in major fire at Auckland's Penrose

Three people have been injured – one seriously – in a major building fire at Auckland's Penrose as thick smoke is sent billowing across the city this afternoon.

Fire and Emergency NZ was alerted to the blaze on McNab St at 3.23pm, with crews from Ellerslie, Onehunga, Ōtāhuhu, Remuera, Auckland City and Mount Wellington responding.

Hone St John was notified at 3.29pm and responded with two ambulances and one rapid response unit.

"Hato Hone St John treated three patients," a spokesperson said.

One person has been taken to Middlemore Hospital in a serious condition, while two others in a moderate condition have been taken to Auckland City Hospital.

Smoke was visible from the Southern Motorway and across the city, including Sylvia Park, the North Shore and East Auckland. Traffic is backed up for several kilometres in both directions on the motorway.

Footage from the motorway showed flames and thick smoke from the building around 3.46pm.

A smoke advisory was issued by Fire and Emergency this afternoon.

"A building fire on McNab St, Penrose is creating a lot of smoke," Fire and Emergency said.

"Residents in the Penrose and Onehunga area are advised to close windows and doors."

A 1News reporter at the scene said a Vector building is on fire. Police said power outages had been reported in parts of Penrose following the blaze "and some intersections are without power".

"Police units are assisting with traffic management at some intersections. Motorists, please take care on the roads."

The nearby suburb of Ellerslie was also hit with power outages.

Fire and Emergency New Zealand has been contacted for further information.

A detour is in place for bus route 66 through Rockfield Rd, Main Highway and Penrose Rd, Auckland Transport said. Buses will not stop on Maurice Rd, Olive Rd, Penrose Station/Station Rd, 29 Station Rd, Penrose Station/Great South Rd and Prescott St.

"This may cause delays."