The nation's peak welfare body, the Australian Council of Social Service, has accused the Turnbull government of a breach of faith over plans for a crackdown on welfare payments and a backdown on superannuation changes.

As Prime Minister Malcolm Turnbull softens the ground for potential compromises on the superannuation package to appease irate conservatives inside the Liberal Party, ACOSS says the government's apparent post-election priorities are a disappointing betrayal of constructive discussions with them and other groups.

"We've had the first clear indication from the government that it is absolutely determined to make major cuts to incomes and living standards of people who are the poorest, they're living on the lowest incomes in Australia," ACOSS chief executive Cassandra Goldie told Fairfax Media.

Social Services Minister Christian Porter recently revealed $5 billion in welfare savings he wants to legislate by September, including data-matching recipients, increased disclosure requirements, reviewing disability support pensioners, reducing carer payments and halting carbon tax compensation for new recipients.