Social Services Minister Scott Morrison has given the clearest signal yet the government will tighten the assets test for people on a part-pension and drop plans to index pensions at a slower rate.

But Labor leader Bill Shorten said the government should keep its pre-election promise not to touch pensions and "stop breaking promises", while the ALP released modelling it said demonstrated pensioners would be worse off under the tighter asset test.

The 2014­–15 budget set out a plan to change indexation arrangements for the aged, disability support and veterans' pensions, carer payments and the single parenting payment designed to save $449 million over five years.

The change would have seen those payments grow more slowly, over time, in line with inflation, rather than in line with CPI or the Pensioner and Beneficiary Living Cost Index and then "benchmarked" against Male Total Average Weekly Earnings.