Four in five people living on pandemic-boosted welfare payments will be forced to skip meals if the coronavirus supplement is cut.
Almost half of recipients will also have to ration their medicines, a new survey has found.
More than 2.2 million job seekers, young people and parents have received an extra $550 per fortnight throughout the coronavirus pandemic.
The Morrison government plans to slash the top-up payment by $300 in less than two weeks' time.
This will leave two in five people living on less than $14 a day after paying their rent.
More than half of survey respondents said the looming cut would make it much harder to pay rent and bills, and they would need to forgo some essentials.
The Australian Council of Social Service is using the findings to ramp up pressure on the government to keep the supplement in place.
ACOSS chief executive Cassandra Goldie called on the coalition to immediately extend the current income support beyond September and legislate a permanent boost to JobSeeker and other welfare payments.
“People are really struggling with the uncertainty of not knowing how they will cover the basics they need to get by, including their rent, with this devastating cut of $300 per fortnight just two weeks away and then another threatened at Christmas time," Dr Goldie said.
"The best way to support those hardest hit by the recession and support economic recovery and jobs is to provide the certainty of a permanent, adequate rate of JobSeeker and other social security payments without delay."
More than 90 per cent of survey respondents also feared an 'extreme' or 'significant' impact on their finances if JobSeeker returned to the old rate at Christmas.
Additional reporting by Evan Young.
