Dumped cabinet minister Eric Abetz wants the federal government to slash spending instead of looking to “gouge” more tax from well-off Australians.

The coalition leadership team says everything is on the table as it looks to change the tax system, including tweaking superannuation tax concessions.

“I would counsel on looking at the expenditure side rather than the revenue side,” Senator Abetz told Sky News on Thursday, arguing targeting those who do well is “lazy”.

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Assistant Minister to the Treasurer, Alex Hawke, said there wouldn’t be any retrospective changes to superannuation.

“We’re not going to penalise people for past behaviour,” he said.

Some existing concessions were viewed by everyone as a “little bit unfair”, he added.

Treasurer Scott Morrison has, in recent days, acknowledged that a Deloitte Access Economics model of super tax reform is being discussed.

The plan would seek to remove the 15 cent flat tax on super contributions, in favour of a 15 cent discount on a saver’s marginal income tax rate.

The government has stressed that although it is “open” to such discussions, it has not made any policy decisions in this area.