An Auckland doctor has failed in her appeal against seizure of patient files as part of a fraud investigation.

The Court of Appeal rejected a raft of challenges by Dr Judith Gill to a raid on her practice, Auckland Metro Doctors and Travelcare, in November 2008 by Ministry of Health officials and police.

The lawfulness of the raid, carried out under search warrant, was previously upheld by High Court judge, Justice Hugh Williams.

As a result of the Court of Appeal ruling, ministry officials can now "urgently" apply for the paper and electronic files, which were subsequently lodged with the High Court, to be returned so that they can complete their criminal investigation.

The judges said that rather than waiting the outcome of the ministry investigation, Dr Gill had launched a pre-emptive challenge to the lawfulness of the search warrant issued by the District Court and to its execution.

In its written decision, the appeal judges said that following an audit and investigation ministry officials believed they had good cause to suspect that Dr Gill had been dishonestly claiming public funding through the inappropriate enrolment of patients on her Primary Health Care Organisation Register, which provides up to three years' funding per patient.

Those patients allegedly included transitory overseas visitors and New Zealanders attending for travel vaccinations but who did not choose Dr Gill as their primary health provider.

The judgment said that when applying for the search warrant, a ministry investigator listed 9276 "names comprising a portion of the patients enrolled on Dr Gill's PHO Register in respect of whom fraudulent claims were suspected and whose patients records from the practice were sought".

Several weeks after the search, Dr Gill challenged the validity of the search warrant, as a result of which all the files seized were placed with the High Court and the criminal investigation was suspended.

In rejecting all Dr Gill's challenges, the appeal judges said this was not an appropriate case for judicial review.

They granted the ministry a 100 percent uplift in costs, which would still see it recover only a third of its actual costs.

The judges said the next step was for the ministry's investigation to be re-activated "without delay" and any application for the release of the documents from the High Court "should be treated with urgency".