Prices on the federal government's GROCERYchoice website should be updated weekly, a key senator says.
Nick Xenophon also wants the site to name the 10 cheapest supermarkets in each region across the country.
The independent South Australian senator, who helped kill off the government's planned petrol price-monitoring scheme last week, plans to use parliament to push for changes to the website.
GROCERYChoice prices are updated monthly.
"If the supermarkets sold food as out of date as this website, they'd be shut down," Senator Xenophon said.
"The changes may cost more, but right now we are paying a fortune for worthless information."