Super change key to budget repair:Morrison

Treasurer Scott Morrison is adamant planned savings from changes to superannuation need to be legislated, otherwise cuts will have to be made elsewhere which he says isn't fair.

The changes to super, including a $500,000 lifetime cap on extra contributions, would save over half a billion dollars and help get the budget back into balance at a time when Australia's triple-A credit rating is at risk.

"If those savings aren't found in that way they would have to be found in other ways, which I think would be more unfair to other people," Mr Morrison told Sydney's 2GB radio on Tuesday.