Biosecurity officials say the genetic engineering "contamination" found in weeds outside a Plant and Food Research containment glasshouse at Lincoln appears to come from GE seed, which regulators allowed Massey University to import nine years ago.
Regulatory controls on approval for Massey's research were retrospectively changed in November 2006 to "future proof" the decision, official records show.
Wording of the control on breach of containment was altered, and the Environmental Risk Management Authority removed altogether a control requiring facilities to be inspected by Erma or enforcement officials.
Plant and Food's chief executive Peter Landon-Lane - whose staff last week found the GE "escapes" in two mustard-like plants (arabidopsis) outside the glasshouse - said when the find was disclosed: "It is unclear how these seedlings came to be outside the facility as they do not match to any work Plant & Food Research has done.
"There is evidence suggesting they have come from a third party."
Plant and Food has been given about 30 different approvals to genetically engineer the plants, commonly used as a "model" in genetic engineering studies, but the Erma website showed Massey only ever received one approval for arabidopsis species.
The purpose it gave for the application was to import genetic modifications "required to support research and teaching efforts concerned with understanding basic mechanisms controlling plant growth and development".
A critic of some uses of genetic engineering technology, Soil and Health spokesman Steffan Browning, who discovered a previous case of "leakage" on a Plant and Food field trial site a year ago, told NZPA a key question was how the GE construct found in the open at Lincoln escaped containment.
One possibility was the plants or seeds had been spread by humans.
But any breach of containment raised questions about the integrity of containment programmes, the conditions set by regulators such as Erma, and their enforcement by agencies such as the Ministry of Agriculture and Forestry's (MAF) biosecurity arm.
Erma has declined comment, but MAF said the GE plants found outside the glasshouse appeared to contain constructs for which Massey had received approval.
Mr Browning last year found engineered kale plants re-growing in a cleared field trial plot, and Plant and Food scrapped its 10-year trial of GE broccoli, cauliflower, cabbage and forage kale at that site.
He today expressed concern the plants, which had been contaminated in the latest incident are also brassicas -- closely related to cabbage, rocket and mustard, with a lot of weedy relatives.
The discovery indicated a need for extensive screening of such plants around Lincoln to find out how far the genetically engineered construct had spread. He called for testing of organic brassica seed saved from the Lincoln area last summer to be included in independent testing.
Finding the extent of the spread and cleaning it up could help protect non-GE producers with high-value organic crops from losing their markets, he said.
Mr Browning questioned whether "sloppy working practices" he had found in the field trial of kale were also occurring in laboratories and containment greenhouses, and claimed Plant and Food had been aware for a long time of "containment ruptures" in the Lincoln area.
Plant and Food has declined comment, but has said its containment glasshouses were used by other research organisations.
Massey researchers applied in June 1999 to import GE seed from plants with changes ranging from herbicide resistance, to added material from rats and various reporter and marker genes.
Erma said at the time Massey must contain the plants in a transgenic plant house, with extra measures to prevent pollen or seed loss.