The Insurance Commission of WA says higher than expected costs of care are to blame for an underwriting loss in its Motor Vehicle Fund, which backs the state’s Catastrophic Injuries Support program.

The fund recorded an underwriting loss of $55.1 million in the six months to December 31, worse than the budgeted $400,000.

“The large underwriting loss is primarily due to the forecast cost of care being higher for scheme participants who have, on average, been more severely injured than was initially actuarially projected,” the commission says.

Its Third Party Insurance Fund, backing the compulsory third party scheme, made an $11.6 million underwriting profit compared with a budgeted $8.8 million.