New data shows 2030 people have died after receiving an initial robodebt letter, which doesn't set an amount to be paid back, but asks them to confirm their previously submitted income information. Of those that were told they did owe money to the department, 812 have died.

Of the 2030, some 663 were considered "vulnerable" by the agency, which includes people who have serious mental health issues, intellectual disabilities, are experiencing homelessness or escaping family violence.

The figures cover a period starting in July 2016 and ending October last year, but those with vulnerability markers were only included in the robodebt process midway through 2018.

Greens Senator Rachel Siewert asked for the information and said that while the figures did not prove a causal link between someone receiving a notice and dying, it showed a problem.

"Particularly when you look at the number of people that had vulnerability markers, 663 is around 32 per cent. I find that quite disturbing and worrying," Senator Siewert said.

"It does look concerning when you first look at the data and I'd say it should be a cause for concern for the department to look at."

Human Services Minister Michael Keenan said the rate of death among the 925,728 people who received debt notices was lower than the rate of death for general Centrelink recipients.

"A total of 2030 of those who received a letter died during the same period, which represents a death
rate of 0.21 per cent," Mr Keenan said.

"This rate was more than 10 times lower than the overall death rate for all of the Department’s customers during the same period, which was 3.64 per cent."

The minister also emphasised the average of 222 days between someone receiving a letter and dying.

"Any number of factors in an individual’s life could have contributed to their death during such an extended period and it would be foolhardy to draw a link to one particular cause without evidence to support such a claim," the minister said.

Senator Siewert called for Centrelink to investigate the data to ensure the robodebt notices weren't contributing to people's deaths.

"If it looks like there is a correlation then there is a duty of care to follow that up to see if there's causation there. Or if it's a person with vulnerabilities, is this something that escalates an existing illness or concern?"

The department said it carefully considered how to deal with people with vulnerability markers, and that all correspondence to those with the markers had a dedicated phone line for those people to call.

The average debt raised for those who died was $2377, but of those who died, only 44 had estates considered sufficient enough for Centrelink to make a claim, while 358 did not.

Of those who died after being issued with a debt, 505 had already made at least one payment before they died.

About 1400 of those who died were still receiving payments from Centrelink, with 520 of those who died were receiving the disability support pension, and another 503 receiving Newstart. Just 252 of the current recipients who died after receiving an income confirmation letter were receiving the aged pension.

The Department of Human Services told the Senate committee that it was aware of media reports about people who had committed suicide after receiving letters or debt notices from Centrelink, but had no information of its own about suicide or self-harm related to the program, which has sent out almost a million notices. Information also wasn't available on whether any of the people were referred to social workers or Lifeline.

Support is available for anyone who may be distressed by phoning Lifeline 131 114; Mensline 1300 789 978; Kids Helpline 1800 551 800.