ACC Minister Nick Smith has ruled out an independent review of elective surgery decisions unless the accident body begins losing a larger number of disputes.

Dr Smith emphasised it was difficult to determine whether elective surgery was required primarily as a result of an accident or an underlying condition.

"The key for me is that the decisions are being made by medical professionals not on the basis of trying to save anybody money but on the basis of where the case fairly falls."

Where claimants were dissatisfied with the decision they could have it reviewed by ACC-owned Dispute Resolution Services and, if necessary, in court.

"At the moment ACC is well and truly winning the majority of those cases. That indicates independent reviewers are finding ACC is making fair decisions about the eligibility for elective surgery.

"If I see ACC losing - the reviewers and the courts finding that ACC is unfairly making decisions about ACC's elective surgery entitlements - that would be the sort of trigger ... for some sort of independent review."

ACC's success rate in review hearings declined to 65 per cent in the last financial year from 70 per cent the year before.

Auckland accident lawyer Philip Schmidt, who last year wrote twice to ministers and MPs asking for an independent investigation into issues around the rising rejection rate for elective surgery claims, yesterday said the 35 per cent of review cases ACC was losing should already be of concern.

He said ACC's success rate was also inflated by counting as wins those reviews initiated by claimants who later gave up for lack of resources. Claimants who represented themselves were rarely successful but Mr Schmidt believed a majority of those who engaged lawyers went on to win their claims.

"The review is no longer a test of the quality of the decisions. The review is really about who can afford representation ... People are basically costed out of the process."

Even if claimants won, they were only entitled to costs of up to about $550, which would pay for only about 1 hours of a lawyer's time and barely half the cost of a medical report.

"We have a system where we are funding a disputes process that is heavily skewed in favour of the insurer. ACC's costs for litigating a matter are 100 per cent subsidised by the taxpayer but the claimant is no longer entitled to a reasonable contribution to their costs even if they win."

Labour's ACC spokesman, Chris Hipkins, who last week joined calls for an independent review, said the disputes process undermined one of the original aims of ACC "to take lawyers out of the accident claims process".