Professor Collignon said the risk to any individual was likely to be low but more significant across millions.

"We should not have antibiotic resistance genes multiplied up by crops growing the genes and having more risk to us for even more problems with superbugs when that is a risk that doesn"t have to be taken," he said.

The Greens, back by Independent Senator Nick Xenophon plan to introduce legislation requiring food labelling to reveal GM content, allowing consumers to choose whether or not to buy products containing GM ingredients.

Greens Senator Rachel Siewert said mothers were buying infant formula, expecting it to be safe.

"Unbeknown to mothers and fathers they are feeding their children infant formula that has been contaminated," she said.

"Parents are not being informed so they can"t makes choices as to whether want to buy that product or not."

Senator Xenophon said consumers were being treated like mushrooms on GM food ingredients, kept in the dark and feed rubbish.

"This has been exposed as a result of Greenpeace, a non-government organisation doing the testing. You have to ask what on earth have our food regulators responsible for food safety standards been doing," he said.

"Food Standards Australia New Zealand needs a kick up the backside for their lack of action on this."

Senator Xenophon said there were too many scientists and scientific papers saying GM health effects were unknown.

"And if you adopt the precautionary principle, as you should particularly ... when you are talking about infant formula, then consumers have a right to know, parents have a right to make an informed choice as to whether they buy a product with any GM contained in it at all," he said.