Concerns have been raised about the cost of WA’s proposed no-fault compulsory third party scheme, which Premier Colin Barnett has hinted will be introduced in this year’s state budget.

The state published a green paper in October and invited submissions, with more than 2000 responses received.

The average premium of $291 for a family car will rise by $109 – including GST and duty – if all catastrophically injured people are covered under a proposed change that will see the state move to a no-fault system.

National Disability Services (NDS) WA has joined the RAC in condemning the increase, despite welcoming the introduction of a no-fault scheme.

NDS says the additional $109 is “inflated in comparison with other states and requires further independent analysis”.

Its State Manager Julie Waylen says a Productivity Commission report in 2011 estimated costs at $37 per person. “What has happened since then? We have asked for a detailed breakdown of the estimated costs, but we have not been given enough information.”

The RAC surveyed 1833 people, including 980 members, and found most are in favour of a no-fault scheme but the $109 increase is a “significant cause for reticence”.

“We have genuine concerns that this figure does not reflect the true cost of introducing such a scheme, and also that it incorporates an element of double charging and cost shifting,” it says.

The submissions will be reviewed by the Insurance Commission of WA, before being published on its website.

The commission will then prepare a report for the State Government.

About 92 people are catastrophically injured in WA vehicle crashes each year, and about 44 receive no compensation because they cannot assert fault against another driver.

Mr Barnett says the cost increase has not been finalised, but the additional charge will not be used to raise revenue elsewhere.