Most of the trees were less than 1m high, and were part of two experiments due to run for two to three years, one testing herbicide resistance and the other was looking at reproductive development.
Scion said not all the trees were genetically modified as the experiments included some control trees.
Dr Parker said the trees will be replanted.
"As a Crown Research Institute, Scion has a responsibility to pursue areas of science and technology that offer opportunities for the forestry sector in New Zealand, including gene technologies. While this is a big blow to us and has set back our work some 12 months, we will not be deterred in carrying out our lawful research," said Dr Parker.
Scion said all risk management safety protocols were immediately implemented when the attack was discovered.
Police have inspected the site and all fences have been repaired. Scion is confident that no material has left the site.
Opposition group denies responsibility
President of GE Free NZ, Claire Bleakley, told Radio New Zealand she had "absolutely no idea at all" who was responsible and doubted the person was connected to the organisation.
"This is really the responsibility of a person who is obviously so disfranchised by the ERMA process and their anger at having GE trees regardless of the 95 per cent submissions against it to ERMA.
"The people already done it before and are obviously very concerned GE trees. This isn't an act of vandalism, this is an act of ridiculousness that Scion is going forward with taxpayers money."
Ms Bleakley said police had not contacted the organisation.
She accused authorities of being slack in their monitoring of field trials, and said the organisation maintains visual and photographic reports of all field trials in the country.
Ms Bleakley welcomed a possible further tightening of security, and was concerned about the possibility material from the attack could have left the plantation and led to outside contamination.
Scientists: Years of work destroyed
Former ERMA board member and professor of molecular genetics at Massey University Barry Scott described the attack as "abhorrent".
"Vandalism of this kind is senseless, destroys years of work done by researchers and fails to recognise that New Zealand has one of the tightest regulatory environments on GM research in the world and that this particular experiment was being carried out under strict conditions imposed by ERMA to protect the environment.
"Given the very slow growth rate of pine trees this particular act of vandalism is even more damaging as it will take years of work to repeat the experiments and will impact on the careers of scientists and their ability to generate new scientific knowledge on pine trees that could potentially add economic benefit to New Zealand.
"What is particularly abhorrent about this act is the thinking by those involved that their rights and actions should take precedent over the rights of other individuals, in this case the scientific community, to carry out research that had been considered and approved by ERMA in a scientifically robust and transparent public process that took into account all the risks, costs and benefits of the work.
"A key component of the decision making process is the setting of controls and conditions under which the work could be carried out. This is good risk management practice.
"Scion were meeting these conditions and were legally entitled to carry out this research."
Associate Professor Euan Mason, of the School of Forestry at the University of Canterbury said if people are opposed to GE research they should seek to have the law changed.
"Regulations do not allow use of genetically engineered organisms outside of carefully contained research facilities in New Zealand, and research conducted at Scion complies with the law. If GE is found to present minimal risks of harm to New Zealand then deployment may eventually be allowed and researchers should be able to prepare for such an eventuality without fear that their experiments might be vandalised.
"Delaying research until widespread use of GE is allowed would place New Zealand at a disadvantage compared to countries that permitted research into GE. It is unfortunate that the experiment was destroyed. If people disagree with genetic engineering research under strictly controlled conditions then the proper course is to present their arguments in a rational way and seek to change the law."
