The report found the bottom 20 per cent of couples with children will be worse off by $1209 in 2018-19 due to the main "hip-pocket" measures in the budget, handed down by Treasurer Scott Morrison on May 3. That represented a reduction of about 2.8 per cent in the disposable income of low-income families.

By contrast, the top 20 per cent of families will be ahead financially by about $211 a year, not accounting for changes to superannuation, largely as a result of cuts to personal income tax.

Single-parent families will be even worse off, with the bottom 20 per cent losing out by $1429 in 2018-19 due to measures including cuts to welfare payments and increase to the tax on cigarettes. That was a reduction of about 3.7 per cent of their disposable income.

The report appears to confirm the concerns of Geelong dad Duncan Storrar who caused a stir on Q&A this week by questioning the government's proposal to cut tax for Australians earning more than $80,000 a year while low-income workers like himself, struggling to make ends meet, were likely to be worse off under the budget measures.

The report, written by Associate Professor Ben Phillips from the ANU Centre for Social Research and Methods, models a range of budget measures that directly affect households, such as changes to family payments, childcare, taxation, tobacco excise and superannuation.

"The losses for the middle and top income groups are proportionately much less than low-income families," he said.

"The main impacts in this analysis are from reduction in welfare payments, mostly family payments. Tobacco excise will also more significantly impact lower-income families."

Associate Professor Phillips said he was not making any subjective comments about the budget's impact, just looking at the "cold, hard facts" – but it was clear those earning less would be worse off.

"Certainly the impact is much more down the lower end of the income scale. Mostly single-parents with kids and couples with kids. So if that's Duncan's situation that's probably correct [that he will be worse off]," he said.

"For him, I think it would be more about the impact on the family payments. There'd be no impact on his tax."

Associate Professor Phillips said his report focused on "hip-pocket" measures that were expected to have an immediate impact on household budgets.

Those measures included reduction in welfare payments, mostly family payments.

An increase in the tobacco tax from September 1 next year would "more significantly impact lower-income families". The tobacco excise is planned to increase by 12.5 per cent each year between 2017 and 2020, pushing a packet of 25 cigarettes to $40.

"Low-income families tend to spend more in dollar terms on smoking and certainly, in proportion to their income, it's a much more significant part of their budget than high-income families," Associate Professor Phillips said.

While the tax hikes on smokes were supposed to encourage people to give up or reduce the habit, it was still the case "if you're an addicted smoker and you're low-income, this budget will certainly have a very strong impact".

Income tax reductions, "while relatively small for each person benefiting, do apply to a large number of people mostly in the top 40 per cent of the household income distribution".

"The losses for the middle and top income groups are proportionately much less than low-income families," the report read.

The report also looked at the impact of changes to superannuation but found those changes were "not enough to alter the conclusion that this budget has a regressive impact".

The report did, however, find that the budget will have a lower impact on low-income families than the previous two budgets under the Coalition.

"In the previous budgets, we found low-income single parents and couples with kids were impacted by about 8 per cent of their disposable income and that's a very significant hit. This [is] about half that or even slightly less than half that," Associate Professor Phillips said.

"So certainly, still a strong impact, but not as aggressive and not as big impact as previous budgets."