Australians' diets could worsen if corporate interests are allowed to dominate food policy, experts warn.

The newly appointed National Food Council will gather in Canberra for the first time on Monday to develop a plan aimed at boosting the security and resilience of Australia's agricultural and food supply systems.

But the federal government has been accused of stacking the council with food business executives, which could lead to the creation of policies that favour corporate interests over public health, nutrition and environmental sustainability.

More than 200 people, including top nutrition and public health experts such as University of Adelaide scientist Fran Baum, have signed an open letter to the prime minister outlining their concerns.

"If you want to continue having a food supply system that is basically making Australians unhealthy, then this is great," Professor Baum told AAP.

"If you want to change that, then you need to dramatically reduce their (corporate) numbers and bring a whole lot of others into the debate."

Members of the council include some from academia, such as Curtin University Associate Professor of supply chain management Elizabeth Jackson and University of Queensland's food and beverage accelerator director Christopher Downs.

However, it also features figures such as the CEO of Grain Trade Australia, a policy director from the National Retail Association, the Australian Fresh Produce Alliance's chief executive, and an executive chairman of Bega Group, which owns its cheese brand alongside Zooper Dooper, Vegemite and more.

"So much on the shelves is ultra-processed foods, which are very profitable for these companies," Prof Baum said.

"We're seeing food as an export commodity when we should be looking at it through the ways it can contribute to environmental sustainability and support the health of Australians."

Studies published in The Lancet found Australians were already some of the biggest consumers of ultra-processed foods, which are associated with conditions including high cholesterol, cardiovascular disease and high blood pressure.

While some have argued individuals should take responsibility for their diets, Prof Baum says policy-making bodies such as the National Food Council must play a critical role.

She compared the situation to seatbelt regulation - telling people to wear their seatbelts did not create significant changes in health outcomes, but policy reform did.

The federal government said the council reflected the diversity and complexity of Australia's food system by bringing together people with expertise in small-scale farming, large-scale production and nutrition.

Consultations for the National Food Security Strategy have covered market access, productivity, supply chains and climate change.

"Feeding Australia, guided by the advice from our National Food Council, will enable us to improve food security across our supply chains, no matter what the future brings," Agriculture Minister Julie Collins said.