A commercial office building in central Wellington was abruptly evacuated this afternoon, because engineers deemed it unsafe.

Photo: RNZ / Rebekah Parsons-King

The evacuation order was given at about 2pm and those inside the 13-floor 79 Boulcott Street were given until 4pm to leave the building.

Jacqui Hastie from Wellington City Council's building resilience team said the building's owners had asked a team of engineers to check it.

Following an inspection, the engineers said they were not prepared to certify the building as being safe to occupy after they found cracks in the floor.

The cracks have been there since the building was constructed in the late 1970's but during today's inspection the engineers identified them as being "concerning".

A number of people were seen leaving the building and loading screens, computers and boxes of belongings into cars and taxi vans.

Phil Guerin from Hague Consulting, which operated from the building's third floor, said he was a bit shocked when he received the order to leave.

He did not feel there was any real risk.

Photo: RNZ / Rebekah Parsons-King

"I think the building's well-built and the property managers have been informing us along the way of everything that's happened.

"They did a little more due diligence and found something they weren't expecting so I think they're being better safe than sorry. I hope so - I'd like to come back to the building."

Mr Guerin understood tenants would be given an update in 48 hours and in the meantime he and his staff had been rushing to remove computer screens and essential material so the company could continue to operate.

"Our IT support company has said 'bring us your server and we'll get it up and running for you and you can set up office in our boardroom if you want to' so that's really good Wellington solidarity there."

Another tenant, Akhil Garg, who works on the 12th floor, said he was unconcerned that he had been in a building that was potentially unsafe.

"The building didn't shake, but it's a process and it always takes time to finish processes so I think it's going to be fine. We don't think the building is going to be demolished so we're happy about it."

Online information shows that in 2015 the building had a rateable value of $10.5 million.

Photo: RNZ / Rebekah Parsons-King

The Tourism Industry Association was one of the organisations evacuated this afternoon.

Chief executive Chris Roberts said tenants were told some months ago that a structural issue had been identified, remedial action was planned, and consents for the work had been filed with the city council.

"We received a letter as recently as yesterday from the engineers saying there were no serious concerns and the building was safe to occupy so something has obviously happened between receiving that letter yesterday and today."

Mr Roberts says the organisation had about 20 people working at 79 Boulcott Street, with preparations underway for New Zealand's main tourism conference, TRENZ, which is due to take place in Dunedin in May.

"We've had to move out lots of gear and equipment to be used at that trade show so we've been filling up staff cars with gear and putting it in storage at one of the team's garages in the meantime."

Mr Roberts said the team could operate from home in the short-term but alternative arrangements would have to be made if the office block was unusable for a longer period.

Meanwhile, he had a positive message for tourism operators.

"It's not quite business as usual, but we'll still be operating and as far as TRENZ goes, there are no concerns there. The tourism trade show in Dunedin in May will be as big and bright and spectacular as ever."