The ACT has spent almost $500,000 on emergency support for people falling through the cracks in the NDIS since July last year, when it introduced a $1.8 million response team and lifeline fund.

In Tuesday's upcoming ACT budget, just $200,000 will remain in that fund for the next financial year and nothing beyond, though it is understood the need for the last resort money will be reviewed if demand continues.

But $40.5 million will be added to the $716 million the territory is spending all up on the scheme over the next four years as part of its agreement with the Commonwealth. More than 500 Canberrans are expected to join the NDIS in that time.

The extra funding will keep a number of existing ACT disability services running including the taxi subsidy scheme and the children's equipment loan scheme, which provides specialist paediatric equipment and assistive technology.

Minister for Disability Rachel Stephen-Smith said the investment would future-proof the scheme in the ACT, the first jurisdiction to sign up to the NDIS in 2013, and help keep services free and accessible.

"Even for those who are participants, the scheme is not intended to meet every need," she said.

The Coalition has promised a major shake-up of the $22 billion national scheme amid harrowing stories of people forced into hospitals or knocked back for essential services under the mammoth national reform.

Four years in, many of the 6,844 Canberrans on NDIS support plans are thriving and the number of disability providers has shot up. But the same troubling stories have dogged its roll out in the capital.

A number of local services have closed or are struggling to stay open after losing funding under the new NDIS model, which puts money in the hands of participants rather than providers in order to better facilitate individual choice and control.

On Friday, the ACT Council of Social Service and peak body National Disability Services said the sector still had grave fears for a market failure in the ACT.

But a government spokeswoman confirmed there will be no extra money set aside in Tuesday's budget to fund services not covered by NDIS criteria.

The National Disability Insurance Agency, which runs the scheme, said some areas had always been thin in the market but a detailed analysis of gaps in the sector was now underway nationally.

Earlier this year, an ACT assembly inquiry called on the government to step up to fill gaps in the sector under the scheme. But while the territory has agreed to continue advocating for people under the NDIS, it said many of the inquiry's recommendations rested with the Commonwealth.

In the latest federal government cabinet reshuffle this month, the scheme was carved off from the department of social services and put under the remit of a new minister - National MP Stuart Robert.

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