Police are seeking more information from the public after hundreds of genetically-modified trees were attacked in Rotorua.
The 357 radiata pines were part of a trial conducted by forestry research institute Scion to study herbicide resistance and reproductive development in genetically-engineered pines.
The trees were destroyed in the attack, believed to have happened between Monday and Tuesday morning.
Police say a security partrol noticed the break-in at the site on Tuesday morning. Scion says those responsible worked through two security fences and dug under a third to dig out or cut off the young trees.
Police say they are not prepared to speculate on who is responsible, but public information is critical in finding out who destroyed the trees.
Scion says it may have to spend about $20,000 on security measures to prevent further break-ins.
Forestry Institute president Andrew McEwan says it appears the vandal has an objection to the project but has not been able to influence public opinion through the normal process.