French-owned Aventis has begun legal action against Victorian Greens Senate candidate Scott Kinnear to force him to return a handful of canola seeds believed to be genetically modified and allegedly found in the shoes of workers harvesting trial crops at Mount Gambier in March.

Last week, Aventis' lawyers wrote demanding the return of the seeds within seven days and threatening further action if Mr Kinnear did not comply.

The latest report by the Interim Office of the Gene Technology Regulator has found breaches of regulations in 23 of 98 former GM trial sites that it monitored between January and March this year. At one site in Tasmania, it found feral GM canola flowering among GM opium poppies, grown to produce morphine.

Last week, questioned by the Senate Community Affairs Committee, Liz Cain, head of the regulator's office, was cited as admitting concern about the behavior of companies such as Aventis and Monsanto in their management of the field trials, saying that under legislation to come into effect in two weeks, a company's track record would be considered in determining approval of future trial licences.

Strict guidelines control the use of GM plant material to avoid contaminating other crops.

Mr Kinnear said yesterday he would not return the seeds to Aventis; instead, he wanted them tested as part of an investigation by the regulator.

A regulator spokeswoman said the incident had been investigated but the woman who had found the seeds in her husband's shoes had since moved and not responded to questions. The seeds would be tested.