A Rotorua research company says it can't keep beefing up security around its pine trees.
Almost 400 genetically engineered radiata pines at the science centre were destroyed over the weekend - either pulled out or cut off.
The trees were planted last year to test herbicide resistance.
Scion Research chief executive Warren Parker says a similar break in about three years ago caused a rethink of security.
But he says no matter how much security's in place, determined people will get through.
"We've got a limited budget and we do want to have some money left over to actually do the science. New Zealanders should be able to undertake lawfully activity safely."
He says this was an act of vandalism and whoever's responsible went to a lot of effort, breaking through security fences.
"This was a legally approved trial and it had been done so under the auspices of the Environmental Protection Agency which had approved us to be able to undertake the trial under containment."
Mr Parker says the destruction's cost the company $400,000.
He says the company isn't deterred and he'll be meeting with the board this week.
Massey University Professor of Molecular Genetics Barry Scott says it's a major setback for researchers.
"Particularly with pine trees because it just takes so long to grow compared to grasses or clover or something like that which you can replant and grow quite quickly."
Mr Scott says it's abhorrent that some people think their rights and actions should take precedent over the rights of other individuals - in the case the scientific community.
Massey University Professor of Molecular Genetics says it's unfair and malicious, especially as Scion was adhering to all protection conditions required.
"I think that this is just a problem we have with new tech in general, there are always some who are fearful of them, don't understand them perhaps just simply don't like them."
Rotorua Police are appealing for information about the attack.
Detective Senior Sergeant Zane Smith says there's been a significant effort by someone to cut through perimeter fencing and get into the secure area.
He says it would have taken a determined approach and quite some time.
Police won't speculate on who might be behind the attack, but say public information is critical in finding those involved.