The VicHealth research, released on Friday, showed one in four families (26 per cent) were forced to rely on nutritionally-lacking food as households felt the financial pinch of the first wave.

Of 2000 surveyed participants, low-income (49 per cent) and single-parent families (39 per cent) were the most likely to buy unhealthy food due to a shortage of money.

Those same groups couldn't even put food on the table at times, with single-parent (27 per cent) and low-income families (11 per cent) running out and unable to afford more.

VicHealth chief executive Sandro Demaio said the ripple effects of this year's devastating bushfires, drought and coronavirus pandemic had put significant strain on home budgets.

"It's having a concerning impact on children's diets," Dr Demaio said in a statement.

"All families want their kids to grow up healthy and strong, but this new research shows that due to budget pressures many are having to rely on cheap, unhealthy food to feed their kids, and some are even going without food."

Dr Demaio is calling for governments to step in to arrest the inequity, with recent data showing kids in poor areas were more than twice as likely to be above a healthy weight than their rich counterparts.

"The gap between rich and poor is continuing to widen," he said.

"This year there's been a hefty increase in the cost of healthy food, like fruit, vegetables, seafood and meats, at a time when families are losing their jobs or having their hours dramatically cut back.

"We must do all we can to support families to ensure they can access and afford to feed their kids healthy food."

VicHealth is doing its bit, planning to announce more than $1 million in grants for community groups that help people stay physically and mentally well during the pandemic.

Australian Associated Press