'Super tax changes will be targeted'

Changes to superannuation tax incentives in the federal budget will be designed to make the system sustainable and fair, and one that offers certainty and choice, Treasurer Scott Morrison says.

Mr Morrison said the government was "close to a landing point" on proposed changes but maintained the purpose of concessions was to ensure people were more independent in their retirement.

"The primary purpose now, particularly when you're targeting tax incentives, is to target those who are mostly likely to be at risk at being more reliant on a pension payment in their retirement," he told a superannuation conference in Adelaide on Thursday.

Mr Morrison said the government had not a lot of room to move on spending in the budget and every single measure must "carry its own weight".

"If there is a tax concession in the budget, if there's a spending measure in the budget, it has to be able to stack up and carry its weight over time," he said.

"Where it no longer does that or where the purpose has shifted over time, then you've got to recalibrate."