Waikato District Health Board chief executive Nigel Murray has resigned following an investigation into allegations of overspending.

Photo: RNZ/ Joanne O'Brien

An independent inquiry found Dr Murray spent more than the agreed $25,000 allocated for relocation costs.

It also uncovered other unauthorised expenses "involving potential financial breaches of the chief executive's obligations", the district health board said in a written statement.

The DHB held a special meeting this morning behind closed doors to deal with "an urgent employment matter".

The board had accepted Dr Murray's resignation with immediate effect, on the basis he repaid all outstanding amounts.

The board will begin looking for a new chief executive as soon as possible.

A spokesperson said the inquiry report, which was completed with assistance from the Office of the Auditor-General, would not be released publicly.

State Services Commissioner Peter Hughes said he expected senior leaders of government agencies to demonstrate the highest standards of integrity and conduct at all times, especially in relation to the use of taxpayers' money.

"The State Services Commission has been very clear about this expectation in discussions with the chair of the DHB," he said in a statement.

Mr Hughes said the result of the investigation process and Dr Murray's resignation were employment matters between Dr Murray and the DHB.

The State Services Commission has not seen the investigation report or been involved in the decisions stemming from it, so it can't comment further.

The senior doctors' union said it was no surprise Dr Murray had resigned.

Association of Salaried Medical Specialists executive director Ian Powell said senior doctors had raised other concerns about Dr Murray's leadership style, but it was ultimately the spending allegations that spelled the end of his tenure.

'It was clear from a wee while ago now that there was no way, given the circumstances, [that] he could return to work," Mr Powell said.

"The trust and confidence relationship with the board had clearly disappeared."

Dr Murray has been on leave since mid-July. He returned from Canada in mid-2014 to take up the job.

He had previously been the chief executive at Southern DHB and also held management positions at Auckland District Health Board.