UPDATE 11:33AM: More than two-hundred people were evacuated from Auckland's SkyCity Hotel this morning after thick smoke was seen billowing from a vent.

The hotel was evacuated when smoke was seen coming out of vents on the side of the building on Victoria St.

Two fire trucks and about 15 firefighters remain on the scene.

SkyCity spokeswoman Rebecca Foote said smoke had been detected in the hotel's generator room and fire services were on site to deal with the situation.

Foote said they were testing a generator that had problems earlier this year.

“We were testing that it had been fixed but obviously not,” she said.

The smoke was found in the SkyCity hotel and not the tower itself, which remained unaffected.

"We're just doing an evacuation of SkyCity hotel at the moment," she told the Herald.

"We're pretty sure it's contained, it's just as a precaution."

Two fire trucks are on scene with around 15 firefighters working to put out the fire. (Photo / Luke Kirkness)