Aged care providers that are registered or considering to register to deliver NDIS services will not know until late this year what the final design of the disability insurance scheme could look like.

Last Friday Treasurer Scott Morrison handed down the terms of reference for a review into the cost of the NDIS that is being undertaken by the Productivity Commission.

It follows reports earlier in the week that the costs of the scheme could exceed $1 billion, sparking fears it could be capped, delayed or cut altogether.

The $22 billion scheme is due to be fully operational and assisting 500,000 Australians by 2019.

The terms of reference specify a review of the sustainability of scheme costs, jurisdictional capacity, cost pressures (including wages pressures), changes in the agreed escalation parameters, if efficiencies have been achieved within the scheme and whether there has been any impact on mainstream services.

The Commission has also been asked to examine the most appropriate levers to manage any potential cost overruns.

While the review had always been planned for 2017, the Treasurer has said it will inform the final design of the scheme prior to its commencement.

“This review is intended to inform the final design of the full scheme prior to its commencement by focussing on updating initial cost projections estimated by the Productivity Commission and by providing advice on longer-term projections and overall sustainability issues,” Mr Morrison said in a joint statement with Social Services Minister Christian Porter released last Friday.

The Commission will release an issues paper and call for submissions in February, which are expected to be due the following month.

The Commission will have until 20 September 2017 to report back to the Treasurer with its findings.

Providers interested in contributing to the review are encouraged to register their interest with the Commission.