Social Services Minister Christian Porter is on the hunt for savings in his new portfolio, hinting spending cuts on carer and disability payments may be needed to get the budget back to surplus.

In comments that echo his predecessor, Scott Morrison, Mr Porter said on Tuesday night that his portfolio "has to be a contributor to slowing the growth of expenditure down".

Noting that the Department of Social Services spent $137 billion last year - about a third of the federal budget - Mr Porter warned that welfare was growing faster than any "other single budget [area] in government".

In an interview with Alan Jones on Sky News, the former West Australian treasurer singled out support for carers, which he said had been growing at 14 per cent per year over the past decade, as well as the Disability Support Pension.