The Oamaru Whitestone Civic Trust, formed in the 1980s to save heritage buildings in the historic Harbour and Tyne streets area, owns 17 properties, most of them Oamaru stone and in the historic precinct.
In the 2010-11 financial year, it estimated it paid about $11,000 in insurance on the buildings. Extensive work has been done over the past 30 years, including strengthening where necessary.
The earthquake on February 22 caused substantial damage and collapsed many heritage buildings in Christchurch.
Trust chairman Phil Hope fears insurance companies may take a blanket approach to covering heritage buildings throughout New Zealand with increased premiums.
He said the trust had had no notification from its insurers after the two Christchurch earthquakes that premiums would rise.
"We know some insurers are looking at increasing cover - a lot has been written about that already," he said.
"It's a matter of waiting to see how that will affect us."
His view was that insurers would probably take "a blanket approach" to increasing cover, rather than approaching it building by building and on an area's risk of earthquakes.
Mr Hope pointed out earthquakes were only one component of insurance. In some cases, when the trust had carried out work on its buildings, it had also done strengthening.
For example, the parapet on the harbour board building - the trust's own offices - and the decorative Oamaru stone on the top of the Criterion Hotel had been strengthened to ensure it would not topple in an earthquake.
The interior of the Smith's building between Tyne and Harbour streets had been strengthened.
"But, I anticipate there will also be a call for increased strengthening in the future," Mr Hope said.
Other buildings owned by the trust, particularly those constructed of large blocks, did not need strengthening and performed better than other stonework, he said.
