The occupants of a white ute may have information that could identify those responsible for an attack on genetically engineered pine trees at a research site in Rotorua.
Police investigating the Easter weekend attack, when 375 radiata pines at Scion's forestry research institute were either cut or pulled out, are appealing to the public for more help to track down the vandals.
It is estimated the vandals caused about $400,000 worth of damage and put research back by a year.
Detective Senior Sergeant Zane Smith says police want to speak to the people who were using a white ute with a white canopy, which was seen parked on a track in a property adjacent to the Scion research site.
"We hope that these people may have information which could help our inquiry," he said.
Anyone with information about the people involved in the incident, or who saw anything out of the ordinary in or around the Scion property is being urged to contact police.
Scion chief executive Dr Warren Parker says the field trial, which was looking at resistance to herbicides and reproductive development, was approved under one of the strictest regulatory regimes in the world and that containment controls were complied with.
"Despite this, our research opponents were determined to stop us and used criminal means to do so."
The Easter weekend attack was the second time GE-trees had been vandalised at the site, and security had been boosted since a 2008 incident when similar damage was done.