Older people will be the target of an expanded "robo-debt" collection measure the Department of Human Services has confirmed will raise close to $1 billion.

Despite the fall-out from the government's debt collection saga, the DHS will expand the program from July 1 using information from the Tax Office about pensioners' interest earnings and asset values.

Pension recipients earning interest on term deposits and income from property are expected to shoulder most of the $980 million savings burden the government has projected over the next three years from the expansion of its debt program.

The department will check ATO data against the income and assets clients reported to it to decide whether to pursue debts, DHS officials told senators.