Pressure to increase welfare payment rates is ramping up ahead of the federal budget as more than 300 advocates, politicians and notable Australians pen an open letter to the PM.

Current and former MPs from across the political aisle along with economists, business and union heads have called on Prime Minister Anthony Albanese to listen to the government’s economic inclusion advisory committee.

Last week, the committee recommended a substantial increase to the JobSeeker payment and related working age payments as a top priority.

Treasurer Jim Chalmers talked down the calls by citing mounting budget pressures, including the cost of aged care, defence, the NDIS and health as well as the national debt interest bill.

But the open letter, written by the Australian Council of Social Service and addressed to Mr Albanese, said it was long past time to address the structural injustice of welfare payments.

“We all want the security of knowing that we’ll be supported during tough times,” ACOSS chief executive Cassandra Goldie said in the letter.

“But right now, the rate of income support is so low that people are being forced to choose between paying their rent or buying enough food and medicine.

“Even before the cost-of-living crisis, income support payments weren’t nearly enough to cover basic expenses, but now people struggling to get by on $50 a day face increased deprivation.”

Research by ACOSS in March found seven in 10 people on income support were eating less or finding it difficult to afford medicine or medical care.

Dr Goldie said Australians with the least could not be left behind in the budget, to be handed down in the second week of May.

Signatories include government backbenchers Alicia Payne, Louise Miller-Frost and Michelle Ananda-Rajah, Liberal MP Bridget Archer, independents and Greens MPs on the cross bench.

Grattan Institute chief executive Danielle Wood, Australia Institute executive director Richard Denniss and former Treasury secretary Ken Henry were among the prominent economists who backed the call.

ACTU secretary Sally McManus, human rights activist Craig Foster, Indigenous academic Megan Davis and Climate 200 founder Simon Holmes a Court also signed the letter.