UPDATED 5:32am The Takapuna office tower that more than 80 fire fighters were called to last night had no sprinklers in it.

The DBO block in Como Street is smoke logged this morning and water damaged after the fire broke out on the fifth floor.

Area Commander Denis O'Donoghue says an aerial appliance was used from the outside to get to the window, and firefighters also attacked it from the stairwell.

He says they were lucky the fire was on the fifth floor and in reach of appliances, because if it was on the eighth or ninth, it would have been a much longer battle.

The alarm was raised by way of a private fire alarm. By the time the first crews arrived, flames were leaping out the fifth floor window.

A cleaner was evacuated and there were no injuries. 

A witness said the fire initially appeared to be confined to one floor, but it spread very quickly.

"It was at least a quarter of the floor up in smoke," said the man while the blaze was still raging.

"There are fire trucks everywhere and I saw one with a crane going up. There's water everywhere and smoke everywhere. It's crazy."

The witness said emergency services had last night blocked off both ends of the street, but he had been walking past the site just as the first of the emergency services arrived. "There were firemen and lots of cops."

A bystander said there had been an explosion earlier on and another said they had heard a window smashing.

Videographer Daniel Hines said the fire went to a fourth alarm, so there could have been up to 30 trucks "and I'm guessing 150 personnel".

Hines said the fire had started on about the fifth floor of the 12-storey building and quickly spread to the seventh floor, but had now been brought under control.

He counted five Fire Service aerial units with big ladders, which were used to douse the building with water.

"The initial call came in about 9pm, he said. "They got there so quick to put it out."

Another witness said she saw about 10 to 15 fire trucks and about the same number of police cars.

"It's not in an apartment building, though, so there shouldn't have been many people inside."

The building has a cafe on the ground floor and contains other businesses, including Lumino Dentists.

The fire was put out last night.