A Newspoll survey has shown nine out of 10 shoppers want the presence of GM ingredients clearly labelled on all food products.

Currently products with highly processed GM ingredients do not require specific labelling.

However, the Network of Concerned Farmers said the problem was more complex than labelling. ''There is no proper method for segregation and the test for determining whether or not a [non-GM] crop has been contaminated only gives a yes/no answer,'' spokeswoman Juliet McFarlane said. ''There's no way to tell the percentage of contamination.''

According to the survey, 54 per cent of respondents said they were less likely to buy a GM product, while only 2 per cent said they were more likely to buy it. Public Health Association of Australia chief executive Michael Moore said since the embargo on GM crops was lifted in NSW and Victoria this year, ''the labelling of foods containing GM ingredients is not something Labor has wrestled with''.

The NSW Minister for Primary Industry, Ian McDonald, said, ''There's no credible research that proves GM food impacts on the health of the consumer any differently than non-GM food.''