Morrison sticks by super tax break cuts

Scott Morrison says he wouldn't be able to look into the eyes of poor families who lose welfare payments if he didn't also touch extremely generous superannuation tax breaks.

The treasurer compared the federal government's planned changes to superannuation concessions on Monday to its cuts to family tax benefit supplements, saying savings had to be spread evenly across the community.

The planned changes to superannuation, including a $500,000 lifetime cap on non-concessional contributions, have come under fire from conservative quarters but Mr Morrison is sticking to his guns.

He pointed out the government also wants to scrap family tax benefit supplements and channel that money into childcare payments.

"That's to people who earn a lot less than those who are able to put half a million dollars after tax, after all their other superannuation contributions into their super account," he told 2GB radio on Monday.

"How can I look them in the eye and at the same time say oh no, I'm going to protect this interest over here who's sitting on half a million ... that they want to put into super so they can pay less tax on it?"

Mr Morrison maintained existing superannuation tax breaks were extremely generous but put in place at a time when the federal budget had a large surplus.