Mark McGowan has given his strongest indication yet that WA could join the Federal National Disability Insurance Scheme, saving hundreds of millions of dollars and offloading legal liability for the program to the Commonwealth.

The State Government is reviewing its predecessor’s decision to operate a State-run version of the NDIS, a decision WA Treasury has estimated would add $533 million to State debt by 2020.

The Premier said yesterday the review was still under way, but emphasised that former premier Colin Barnett “without Cabinet endorsement” signed up to a State-based NDIS the day before election writs were issued in early February.

Mr McGowan said the review, to be completed within months, would look at what the best model would be for people with disabilities in WA but admitted financial considerations would be factored in.

“We are investigating that aspect as well to see exactly what the savings would be but there’s also potentially risk associated with the State maintaining a State-based scheme that would not exist if there was a Federal-based scheme, and there is also the cost of setting up an entire new computer system as I understand it,” he said.

Although Mr Barnett inked the deal in a national partnership agreement, Mr McGowan was confident the Federal Act underpinning the scheme could be changed “fairly easily” because the Federal Government wanted WA aboard.

WA Opposition Leader Mike Nahan appeared open to ditching Mr Barnett’s stance, saying “we’ll look at what (Labor) propose at the time they propose it”.

Opponents of a WA-delivered scheme have been calling on Mr McGowan to tear up the existing agreement and join the national scheme, arguing there is “no clear evidence” that a locally administered scheme would deliver better outcomes for West Australians with a disability.

But disability services providers are concerned throwing out the agreement now will put the NDIS back by 18 months in WA.