Under the Government's earthquake-prone buildings policy announced on Wednesday, buildings with a Historic Places Trust (NZHPT) category 1 classification or on the proposed National Historic Landmarks List can apply for up to an extra 10 years - 25 years instead of 15 - to strengthen their buildings to 34% of the new buildings code.
Oamaru Whitestone Civic Trust chairman Marcus Brown feared category 2 or unlisted heritage buildings that did not qualify could eventually be demolished, leaving big gaps in Oamaru's historic streetscapes.
For example, of the 16 buildings owned by the trust, only four were category 1, and a similar proportion could apply to all of Oamaru's heritage buildings.
The Otago Daily Times asked Minister for Arts, Culture and Heritage Chris Finlayson, how the policy applied to category 2 and unlisted heritage buildings in NZHPT registered historic areas - Oamaru has two areas, Oamaru harbour and Harbour-Tyne Sts.
A spokesman for Mr Finlayson indicated heritage buildings with registered historic areas may qualify to apply for the extension, regardless of whether they are category 2 or unlisted.
The extension period in the policy on individual buildings only covered those registered category 1 and entries on the National Historic Landmarks List.
However, it could also include a registered precinct or area, even if all individual buildings in it were not category 1.
''The Oamaru Harbour and Harbour-Tyne Sts historic areas will be considered for inclusion on the National Historic Landmarks List, which will be limited to 50 entries,'' he said.
Mr Brown yesterday welcomed the possibility heritage building owners in the historic areas could get an extension, regardless of classification.
He believed having the two areas included on the historic landmarks list should be pursued, but this was a personal view and a decision the trust board would have to make.
The Oamaru Harbour historic area covers the immediate area around the harbour, but includes part of Cape Wanbrow and the gun emplacements.
However, the Harbour-Tyne Sts area is tightly confined mainly within Harbour-Itchen-Tees-Wansbeck Sts and does not include buildings such as along the west side of Tees St or lower Thames St south of the Boer War monument at Severn and Coquet Sts.
Mr Brown believed there could be scope to extend the area, particularly to lower Thames St, which some people described as ''the heart of Oamaru''.
That could also mean heritage building owners there could also apply for extra time, regardless of classification.
However, that would need to be discussed by the trust's board, in consultation with the Waitaki District Council and building owners, he said.
