The poorest public service pensioners are bearing the brunt of the government's $465 million cuts to their income payments, new official figures reveal.

The Coalition justified its changes to the rules around public sector pensions and Centrelink payments, saying former public servants were earning $120,000 from their employer super schemes and still claiming the age pension.

But nearly 60 per cent retirees who have been hit with cuts to their benefits were on less than one-third of that sum, $41,000 a year or less, and thousands of pensioners were getting by on $600 a week or less, when the axe fell.

The latest official poverty line was $597 a week for a couple and $422 per week for a single person.

At the other end of the scale, it is unclear from the official data how many retirees were getting the annual pension payments of more than $120,000 used by the government to justify the changes, but just 30 singles were on incomes of $2000 a week and 168 couples fell into that combined income bracket.

Retired police officers, firefighters and nurses, as well as former state and federal public servants, saw Centrelink payments reduced under new rules, known as the "10 per cent cap" which came into force on January 1 with the government saying the changes simply brought the rules for retired public sector employees into line with those of other pensioners.

More than 1200 retired Uniting Church ministers or their widows around Australia also saw their incomes slashed in an unintended consequence of the policy change.

Now, official figures from the Department of Social Services show that by January 1, nearly 48,000 people had their income support reduced and nearly 1600 people were cut off outright.

The department is still using the same savings estimates, of $465.5 million over the four-year forward estimates period, that was used in mid-2015 when the policy was before the Senate.

But an analysis of the department's data shows most of the claimed savings, about $277 million, will come out of the pockets of those at the bottom of the income pile.

More than 9000 of the single recipients were on incomes of less than $800 a week, when they faced average cuts of between $21 and $33 a week and nearly 10,000 couples were receiving the same amounts per person when they were hit with the new policy.

Pensioners groups are furious after seeing the figure from DSS with Annette Barbetti of the Superannuated Commonwealth Officers' Association saying retirees were still getting in touch to complain of the unfairness of the changes.

"A lot of these people are very elderly and they live on these very small pensions, and to have money taken away from them, it's just awful," Ms Barbetti said.

She said most retirees were powerless now to change retirement decisions made under a set of rules that had now been arbitrarily changed by the government.

"The overwhelming feedback is that it is very unfair and that if they were going to bring this in then it should have been grandfathered," she said.

"I was talking to one gentleman and he is 89 years old and he's just lost $53 a week, what can he do?"

The retired public servant said she and her colleagues were worried the changes reflected a poor understanding of the complex landscape of public sector superannuation.

"It seems there was very inadequate research, it all seems to have been very badly thought out," she said.