Owners of earthquake-damaged homes can claim a defence against litigation from September 4.

The Residential Advisory Service (Ras) is telling earthquake claimants to get in before it is too late.

Some insurers can claim their Limitations Act defence against litigation as of September 4.

A Ras spokesman said claimants still dealing with EQC should contact their private insurer if there was even a chance their claim could go over cap.

IAIN MCGREGOR/STUFF Earthquake insurance lawyer Peter Woods.

"The thing that I'm most concerned about is those homeowners who might just have a remedial claim with EQC, so they've had some repairs done, but they've got some concerns around those repairs, they should also contact their insurer."

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Insurers have a defence against litigation that starts later than six years after the insured event, in this case the first Canterbury earthquake in September 2010.

All insurers voluntarily extended their limitation period from September 2016 to September 2017.

Southern Response has extended to September 4, 2018, and IAG extended to June 30, 2018.

Annette Purvis, disaster recovery unit general manager at IAG – the company with the most private claims from the Canterbury earthquakes – said the company preferred to settle claims outside of litigation.

"Limitation Act Defence means that should a customer issue proceedings against IAG on or after 1 July 2018 that IAG will raise the Limitations Act as a defence in the proceedings."

Tower has stated its interpretation of the law was that the six-year period applies from the time a claim was settled or rejected, rather than from the date of the original incident.

"I actually think Tower's position on the limitation period is probably right," earthquake insurance lawyer Peter Woods said.

"There is a risk the other insurers will say different, and if they're right, it's fatal," he said.

"We expect that many hundreds, if not thousands, of homeowners in Canterbury are affected."

Woods wrote to the Insurance Council earlier this year, requesting that insurers agree to defer their Limitations Act defence until at least 12 months after EQC notified a claim as over cap.

Insurance Council chief executive Tim Grafton replied, saying the council could not agree to the proposal because the member companies had different approaches to the issue.

"We would encourage all homeowners with unsettled claims to be in close contact with their insurer to understand that insurer's precise position on limitation periods and how that may affect the circumstances of their particular claim, rather than file proceedings first."