Treasurer Jim Chalmers has defended billions of dollars of savings for the National Disability Insurance Scheme, arguing growing costs needed to be moderated.

The budget included $74 billion worth of savings for the NDIS over the next 10 years, with growth of the scheme set to be capped by eight per cent a year from 2026.

Advocates had expressed concern on the size of the budget cuts, but Dr Chalmers said the figures had been based on advice of agencies and the disability sector.

"Our overwhelming priority when it comes to the NDIS is to make sure that people who the scheme was designed to serve get the right services and programs to help them," he told the ABC's Insiders program on Sunday.

"It still will be growing very quick, the quickest growing (item) in the budget, but we need to moderate some of these costs, so in the near term, that's about cracking down on fraud and money going where it's not supposed to be going."

The NDIS is expected to cost almost $42b in the 2023/24 financial year, rising to almost $56b by 2026/27, budget papers showed.

Dr Chalmers said of the $74b in savings, $15b would come from cracking down on fraud within the NDIS, with other savings from the growth cap.

"We're not talking about winding back growth in the scheme, we're talking about moderating it," Dr Chalmers said.

"That reflects the best balance and our best understanding of what we need to do to fund the services that people need and deserve while winding back on areas where that spending has been unnecessary."

The treasurer said the National Disability Insurance Agency, Treasury and the expenditure review committee had been involved in examining costs for the scheme going forward.

The government is conducting a review of the NDIS, with the findings set to be handed down by September.

The treasurer said there would be large amounts of information for people within the disability community about the growth caps and savings for the scheme.