Twelve Whangarei commercial buildings have been found to have construction features similar to the CTV building which collapsed in the second Christchurch earthquake.
Four of the 12 have been cleared but the remaining eight will have to undergo engineering assessment to determine levels of seismic risk.
But Whangarei District Council building compliance manager Bruce Rogers says there is no cause for alarm - the assessments are simply part of a nationwide precautionary review.
The buildings cannot be named yet as the Ministry of Businesses, Innovation and Employment (MBIE) is withholding the information on the grounds that release now would unreasonably prejudice the commercial position of building owners.
The buildings were among 158 identified in MBIE's nationwide search for buildings which might share similar characteristics to the CTV building, following the tragedy.
MBIE was looking for buildings of three or more storeys, which had been granted building permits or consents between 1982 and 1995 and had reinforced columns, in particular on non-ductile (inflexible) columns.
Territorial authorities were asked to forward records of any buildings with these features and these buildings were assessed by MBIE engineering consultants Aurecon.
Aurecon assessed the 12 identified by Whangarei District Council and concluded eight warranted further checks.
Bruce Rogers says it's important to note that buildings identified as having inflexible columns will not necessarily have problems in an earthquake.
"It doesn't mean they are dangerous. There may be no cause for concern at all. Other elements of the seismic resisting may limit displacements to acceptable levels," Mr Rogers says.
Pre-cast stairs were also in the spotlight following the collapse of the stairs in the Forsyth Barr building in the February 2011 earthquake.
MBIE was recommending guidelines on the design of stairs and other secondary structural elements following publication of the Royal Commission report into the failure of buildings in the Canterbury earthquakes, and the WDC had asked the owners of all commercial buildings to have the seismic strength of stairs assessed.
"Pre-cast stairs are lifted into place during construction and if they are not fixed in the recommended way they can dislodge and collapse down on each other as they did in the Forsyth Barr building. The lifts won't be operative after a quake and once the stairs have gone you haven't a hope of getting out," Mr Rogers said.
Government departments and most large businesses have already had full engineering assessments done on their premises, he said. Some had moved out. Affected firms included APN Ltd, publisher of the Northern Advocate (the company has had to urgently address seismic issues at newspaper buildings at Hastings, Waipukurau and Masterton).
Meanwhile, he says, the really big debate rages: Whether existing buildings should be required to be one-third as strong as new buildings (as previously), or upped to two-thirds.
"Some engineers and others are putting the pressure on for 67 per cent ... on the surface it seems like a good idea but if we were forced to go down that line our economy would probably collapse," Mr Rogers said.
"The cost of upgrading to one-third can be significant but is reasonably feasible. Many Whangarei building owners have done this already but a 67 per cent requirement is likely to see people walking away from their properties. Take Vic Hill, who owns Whangarei's Grand Hotel, who has spent hundreds of thousands of dollars on seismic strengthening to the required one-third level.
"Mr Hill has said quite frankly that he could not stay in business if the bar is raised to 67 per cent."
In relation to new-builds the question was "how far do you go before a building becomes prohibitively expensive or a bunker? It's not just about health and safety, it's an economic debate. We are talking about our nation's ability to be productive and keep on developing," he said.
Other big questions were time-frames such as "how long do we give people to strengthen their buildings? Should there be different specifications for buildings of different ages and in different areas?"
But Mr Rogers said the council was reasonably confident the one-third requirement would stand, albeit with some changes.
The good news was that Northland was pretty safe compared to the rest of New Zealand.
Whangarei's clay soils meant slipping was a problem but the district would never be subject to liquefaction.
"And what's pretty safe?" Mr Rogers said. "We have had earthquakes - we had one in 1969. Someone's Christmas turkey fell on the floor, a path and a chimney were cracked and a letterbox fell over.
"Wellington has a one in 50 chance of an earthquake. We have one in 4000. We are talking in the tens for Whangarei compared to the thousands further south."
Mr Rogers says building owners and local authorities will simply have to sit tight until the debate is worked through, and that "keep calm and carry on" is not a bad mantra for the time being.
Get Seismic Savvy
Links to information on earthquake risk
Local impact of earthquake policy
Do we have earthquakes in Whangarei?
Canterbury Earthquakes Royal Commission Final Report Vols 1-3
Why buildings respond differently in earthquakes
Earthquake Facts -Professional Institute of Engineers (IPENZ)
IPENZ consolidated earthquake fact sheet
Review of Earthquake Prone Building Policy by Ministry of Business, Innovation and Employment
Practice advisory 13: Egress Stairs