Police are investigating the destruction of genetically engineered pine trees at a forestry research site in Rotorua.
Scion says 375 radiata pines planted over 1 hectare last year to test herbicide resistance and study reproductive development were protected by electric fencing at the forestry research institute.
Chief executive Dr Warren Parker says the attack over the Easter weekend was an attempt to stop the research.
"Somebody broke in through the three security fences -- dug under the final one - and either pulled out or cut off 375 plants," he said. "It is outright vandalism."
He declined to speculate on who carried out the attack.
Loss of the trees - not all of which were genetically engineered - will cost Scion at least $400,000 and will set back by about a year the eight-year evaluation of whether the technologies involved would demonstrate significant environmental and economic benefits for the nation.
There has been a lot of consultation with the public on setting up the trials, which Dr Parker says include potential for herbicide resistance and production traits such as growing denser wood or timber more suited to pulping.
It's the second time genetically-engineered trees have been attacked on that site: an earlier GE experiment was disrupted in 2008, when similar damage was done.
After that incident, a 4ha site was protected with "high security voltage" electric fencing, electronic alarms and security patrols, but these precautions did not pick up the people who tunnelled under the electric fence.
Dr Parker says Scion will be talking to its board and the scientists about replacing the trees. The original work was State funded.
''Not us'' - GE Free
GE Free New Zealand president Claire Bleakley says she has no idea who was responsible, but doubts it is anyone connected with her organisation.
Ms Bleakley told Morning Report that the trees were obviously cut down by someone disenfranchised by the Environmental Risk Management Authority process to decide which genetically modified research should be undertaken.