Plans to cut down ancient trees surrounding Blue Lake in Rotorua are being criticised by the National Party.

Conservation Minister Nick Smith says the 90-year-old douglas firs should be protected, even though the cutting rights are held by a private company.

"These magnificent trees offer far more to New Zealand and Rotorua for their scenic and recreational value than as timber and pulp," he said.

"There is widespread concern in the Rotorua community about the impacts of this logging on tourism and recreation." Dr Smith suggested the Nature Heritage Fund could be used to buy the trees.

The forest is on Crown land but the cutting rights are held by Kaiangaroa Timberlands, a company jointly owned by Harvard University and the New Zealand Superannuation Fund.

Rotorua MP Steve Chadwick, a Labour cabinet minister, said she had been working on the problem for some time.

"Nick Smith's suggestions for a quick fix are simply wishful thinking," she said.

"The fund is only for indigenous forests, not introduced species like the douglas firs surrounding Blue Lake."

Ms Chadwick said she had met Kaiangaroa Timberlands and the company had agreed to consult the public before making any major decisions.

Dr Smith said the fact that the firs were not indigenous should not make any difference because they were part of New Zealand's heritage.