The federal government reportedly delivered May's budget in the knowledge its spending cuts would have a much harder impact on poor households.
Citing treasury figures obtained via a Freedom of Information request, Fairfax Media says they fall into line with private modelling showing the cuts were sharply inequitable.
Criticised by Opposition Leader Bill Shorten and others for its "unfairness", the budget has proved publicly unpopular to the point of causing a poll slump for the coalition which has been remedied somewhat only by its handling of the MH17 disaster.
Many of the budget's initiatives have also met strong resistance in the Senate, with Treasurer Joe Hockey forced to negotiate their passage with crossbenchers.
The Sydney Morning Herald says when all factors are taken into account, the budget's spending cuts mean an average low income family loses $844 per year in disposable income (earnings after tax and government payments) while middle income earners forgo $492. A high income family is down by $517.
The paper says the analysis is just one of several that was provided to the government in the lead-up to the budget.
It also says treasury refused to release two detailed sets of modelling on the basis they were for "the dominant purpose of submission to the cabinet".