No change to government's super crackdown: Morrison

Treasurer Scott Morrison has ruled out any retreat on the government's contentious plan to limit the superannuation tax concessions of wealthier retirees.

The coalition is facing a backlash from its own supporter base on measures which include capping at $1.6 million the tax-free balance of retirement accounts.

Mr Morrison told ABC Melbourne radio on Friday the decision had been taken and there would be no reviewing the plan.

The free-market think tank Institute of Public Affairs is preparing to campaign against the measures, which also include a $500,000 lifetime cap on non-concessional contributions backdated to 2007.

Critics say the government is applying the changes retrospectively, a view echoed by Tony Abbott's former chief of staff-turned-media commentator Peta Credlin.

The changes were "getting under everyone's skin" and had angered coalition voters.

"It's pretty rich to say it's not retrospective," Ms Credlin told Alan Jones on radio 2GB on Friday.

"I don't think it's thought through."