“These claims are deeply misleading. Taxable income ignores the largest source of income for many wealthier retirees: tax-free superannuation.”

The findings were issued one week after the government floated the 610,000 figure in the media with the claim that these people would lose an average of $1200 a year in tax refunds.

Labor treasury spokesman Chris Bowen seized on the Grattan analysis on Tuesday morning to accuse Mr Morrison of lying to voters by emphasising the policy's impact on “low-income” taxpayers.

“We will call this out on every single occasion,” Mr Bowen said.

The Grattan analysis uses the example of a self-funded retiree couple with a $3.2 million super balance in two super funds as well as their own home, with an additional $200,000 in Australian shares held outside super.

“Even drawing $130,000 a year in superannuation income, and $15,000 a year in dividend income, they would report a combined taxable income of just $15,000, and pay no income tax whatsoever,” Mr Coates and Ms Wood write in the analysis published in Inside Story.

“And is the Treasurer seriously suggesting that 610,000 retirees actually get by on less than $18,200 a year, or nearly 20 per cent below the poverty line? If that were anywhere close to the real story, it would signal a full-blown retirement-incomes crisis.”

The findings go to the heart of the political debate over whether Labor’s proposed tax revenue increase hurts the vulnerable or imposes the biggest burden on those with more assets and more comfortable incomes.

Labor aims to raise $5.6 billion from 1.1 million taxpayers by cancelling the cash refunds, an average of about $5000 from each taxpayer, but it has been slow to produce details on the different groups affected.

Mr Bowen has estimated the policy would reduce cash refunds to about 15,000 people on the full pension, another 200,000 on the part-pension, about 400,000 self-funded retirees and 200,000 self-managed superannuation funds.

The policy also cancels refunds to people of working age with low incomes and large share assets, but Labor has not produced any estimate about this group.

The government warned last week that $2.2 billion would come from people on incomes under $87,000.

The Grattan researchers caution that “assessable income” is a better guide to a household’s income.

“The full story is that many part-pensioners are relatively wealthy, especially because the home is excluded from the pension assets test,” they write.

“Half of all pension payments go to those with assets of more than $500,000. Almost 20 per cent of payments go to those with assets of more than $1 million.

“They’re clearly much better off than the bottom 40 per cent of retirees, who draw a full age pension.”

Fairfax Media readers have responded vigorously to the Labor proposal, with individual retirees warning they stand to lose cash refunds worth thousands of dollars every year.

“Nobody seems to understand that people like me have no super, no pension, no part pension and a low income to boot,” wrote one reader.

Others have warned the Labor plan would force them to draw down on their assets at a faster rate, pushing them onto the age pension and costing the government more money over time.

The chair of the Self Managed Super Fund Association, Deborah Ralston, warned on Tuesday that Labor would not raise as much money as it claimed because it appeared to over-estimate the refunds it would recoup from the sector.