The full cost of a 6.5-magnitude earthquake that shook Wellington yesterday may not be known for weeks, according to the Insurance Council of New Zealand.

“It appears a lot of commercial property has been affected,” the council’s Insurance Manager John Lucas told insuranceNEWS.com.au today.

Four people were injured in the quake, which lasted one minute.

Some insurers are imposing “stand-down” periods, during which they will not provide new cover in parts of the country, he says. “What they are trying to avoid is people insuring uninsured properties that have already been damaged.”

Insurance companies are “gearing up their staff” to handle claims.

But it was not a catastrophic event, Mr Lucas says. “This was a moderate quake that has caused some damage. From our perspective, it is not a big event, but people are nervous and respond differently since Christchurch.”

The quake was part of a series in the Cook Strait area that began on Friday morning.

New Zealand research institute GNS Science estimates there could be up to nine magnitude-five or greater events in the next week.

There is a 30% chance of another magnitude-six or greater quake, but the most likely period for this was in the 24 hours after yesterday’s tremor.

“We need to understand there is a swarm of quakes that will go on for a few weeks,” Mr Lucas said. “We had a 4.9 this morning, but it didn’t feel that strong.”

The Earthquake Commission says residents who suffered damage have three months to lodge claims.

“If it is necessary to take action to make your home safe, secure and sanitary, keep records and photographs of the changes that are made, because they may be recoverable if you have a valid claim,” it said.

Wellington City Council has advised workers to avoid the CBD today while buildings are assessed.