The Australian and New Zealand Green parties today said they would jointly work to get labelling laws changed.

Australian Greens leader Bob Brown is in Auckland to support the Greens in their final push before the election on Saturday.

He joined Greens safe food spokeswoman Sue Kedgley in Auckland's Freyberg Square where members of the public were quizzed about eight products were from. No one got it right. She then took him for a tour of New World in Freemans Bay.

Senator Brown was shocked to be shown products labelled Kiwi that were imported produce.

"The average person is going to believe that was made or grown in this country. I am astonished these products with Kiwi ... are imported... that's straight deception of the shopper."

The Greens want country of origin labelling on all food. They also want labelling to have clearer nutritional information, state whether genetic engineering is used and what chemicals were used in the production.

"What we are both working towards is a very simple labelling system where the ordinary supermarket shopper can see if it's made locally, if it's got a low carbon footprint -- that it's not polluting the atmosphere unnecessarily, if it's got genetically modified ingredients or not, whether it's chemically contaminated and if so by what," Sen Brown said.

Ms Kedgley challenged him to work out the sugar in a box of cereal targeted at children -- but the way it was worded he couldn't. The answer was 1 percent fibre, 36 percent sugar.

"You should be able to read the label to get that simple information as to whether it's what you want to buy; local, chemically free and free of GE," he said.

The two countries share joint food labelling standards developed by Food Standards Australia New Zealand, based in Canberra.

The pair said the shared system meant a joint approach could get results.

"We will seek to introduce parallel legislation in our two parliaments and develop a joint consumer-based campaign on both sides of the Tasman," Sen Brown said.