Growing supermarket profits and rising grocery costs will come under scrutiny when a Senate inquiry looks into claims of supermarket price gouging next year.
Both Coles and Woolworths have recorded more than $1 billion in profits for the past financial year, gains that the Greens say are a result of price gouging at the expense of Australians doing it tough.
The Greens-led inquiry is expected to be established next week with Labor's support, with the inquiry to start in 2024.
Senators are expected to probe the two supermarkets on their price-setting practices when they face the inquiry.
It comes as many families say they been forced to reel in their food spending amid rising interest rates and a cost of living crisis.
"It is about ensuring that Australians can afford to eat without being exploited, and that suppliers are treated fairly," Greens senator Nick McKim said.
"Coles and Woolworths are making billions in profits.
"This inquiry is a critical step toward dismantling the market concentration that's led to unfair pricing and stifled competition.
"It's time to smash the duopoly."
The inquiry will also examine the effects of market concentration, opportunistic pricing, mark-ups and "discounts that aren't discounts", among other issues.
Greens senator Sarah Hanson Young said this was an important inquiry because the cost of living was "going through the roof" and Australians were doing it tough, especially leading up to Christmas.
"The cost of people's supermarket trolley at the end of the week is becoming a really hard thing to bear week in week out" she told Insiders on Sunday.
"I've been talking to parents in my electorate who are wondering whether they should even enrol their kids in the school holiday program. Are they going to have the ability to afford that and the Christmas lunch."
But Nationals leader David Littleproud said the inquiry wasn't enough and would take too long.
Instead, the Nationals want an Australian Competition and Consumer Commission (ACCC) price inquiry, which Mr Littleproud said would have more power to act and compel supermarket chief executives to give evidence.
"An ACCC inquiry could have started the investigation before Christmas and actions from the price inquiry can be undertaken immediately, without having to wait for the completion of the inquiry," he said.
"The Senate Inquiry won't start until 2024 and is mere window dressing for Labor and the Greens.
"Many families are struggling to afford their grocery bill each week and might be feeling overwhelmed by the cost of an upcoming Christmas lunch, so it's important the government acts swiftly."