On Tuesday it was revealed the government would no longer use income averaging data from the Australian Taxation Office to find over payments.

An estimated 600,000 robodebts will need to be reassessed but the government has not advised if it would be lifting a staffing cap to employ the staff needed to do this work.

Community and Public Sector Union Tasmania regional secretary Zac Batchelor said, while the union welcomed the announcement, it was calling on the government to scrap the staffing cap and convert current positions in the Launceston Service Centre to ongoing employment.

"The staffing cap has a huge impact on Centrelink's ability to retain skills, corporate knowledge and efficiently deliver services to our community," Mr Batchelor said.

"In Tasmania this is of particular concern. Since last financial year, Tasmanian Centrelink offices have lost 158 permanent jobs, with the majority of those jobs being replaced by labour hire companies."

Mr Batchelor said, although the DHS does not provide the CPSU details of labour hire staffing numbers in Tasmania, the unions was aware of 170 people working in the robodebt area in Tasmania.

"Of those approximately 75 per cent of those staff would be employed by labour hire companies with no sick leave or holiday pay," Mr Batchelor said.

"We know that these arrangements result in high levels of workplace stress, anxiety and huge levels of staff turnover.

"Staff have reported to their union that the work of issuing robodebts is extremely stressful."

Tasmanian Council of Social Services chief executive Kym Goodes said changes to robodebt would see the number of Tasmanians receiving letters from Centrelink greatly reduce.

She said the impact of robodebt has been particularly high in Tasmanian due to the large number of people accessing income support payments.

"There's also a high number of people who come in and out of casual employment over the course of a year because our labour market is highly casualised," Ms Goodes said.

"That was placing particularly pressure on Tasmanians who were having to come off and on Newstart payments, working when they could get work and having to draw down on that income support when work wasn't available."

Ms Goodes said a greater level of human interaction between Centrelink and those on income support will mean there is less likelihood of either accidental debt or the system inappropriately assessing income against eligibility.

"The devil is probably in the detail of which we haven't yet seen," she said.

"The onus is on the government to get [this] system right, not on people to prove they engaged with that system appropriately."