The Rotorua Museum is the most photographed building in New Zealand. It is also closed.

Built on geothermally heated ground and damaged from an earthquake in 2016, it is nowhere near meeting the building code.

Rotorua mayor Tania Tapsell says fixing it would be one of the most complex earthquake strengthening projects in the country.

"You've got a 115-year-old wooden-framed building, sitting on weak pumice masonry walls, and sitting on top of ... geothermally heated ground - now this is so warm you could cook a pizza on it."

Head next door and you will find the Blue Baths. Also closed, it is even less safe to be in.

Tapsell says that the future of the Blue Baths would be very difficult to solve.

"We have active geothermal activity underneath it, which unfortunately means a high risk of liquefaction."

Drive south a couple of hours and you will find another hugely photographed building, the Chateau Tongariro. It is also standing empty.

Chateau Tongariro. Photo: Brook Sabin/Stuff.

The Department of Conservation now manages it and says it's keenly aware it's a highly regarded heritage building sitting at the gateway to the Tongariro National Park, which itself has Dual World Heritage for its natural and cultural heritage.

DOC deputy director general of organisation support Mike Tully says the department is conducting ongoing routine maintenance to ensure the building remains in its current condition.

"The department is committed to working with iwi and a range of stakeholders on these issues."

A few valleys away, the Waitomo Hotel still looks down imposingly as drivers sweep past towards the caves. But, after years of complex problems leading to a lack of investment, it is also closed.

Waitomo mayor John Robertson says it's sad to see it that way.

"In its time it was just magnificent."

Lloyd Macomber specialises in heritage conservation at architecture firm Salmon Reed.

He says New Zealand is too young a country to have ruins and there's only one thing that can be done about these prominent yet problematic buildings.

"Just apply a lot of money. There's no short way to say that, there's no silver bullet."

Why not just knock the buildings down and start again?

"They really are missed when they're not there. They offer a marker in time of where New Zealand was and what New Zealand was thinking - rightly or wrongly let's just say - for that particular place and location and setting within the country."

Ruapehu District mayor Weston Kirton agrees, and says even though the chateau is an old building it's still relevant to the community.

"The general feeling of the community is that they want to retain it in its former glory."

There's no doubt in Tapsell's mind that the Rotorua community feels connected to its old buildings.

She's committed to getting them open again, though maybe not used in the same way, and she hopes the government will help out with the cost of retaining the buildings long-term.

Tapsell says fixing old buildings up is just one part of the problem; they need ongoing care - even while they just sit empty.

"We are looking after them, but we are also desperately wanting to provide certainly to our community - and also the country - that these significant buildings will have a future."

-Libby Kirkby-McLeod/RNZ.