Auckland Mayor Len Brown's promise to do more to protect the city's heritage has been dealt a blow by council planners who did not tell heritage colleagues about a development next to a listed heritage building at Green Lane Hospital.

Council planners did not notify anyone in the heritage division or the Historic Places Trust about plans by the Auckland District Health Board to build a home dialysis unit within metres of the century-old Building 5.

The single-storey building was granted resource consent in December with no discussion of the possible effects on Building 5. Construction could begin in June.

Health worker Helen Geary, who led a two-year battle to save the old male infirmary ward - known as Building 5 - is appalled at the council's processes.

"I despair of the attention and significance being given to heritage so far in this brave new council.

"So much for the promises by Mr Brown that our heritage will be protected. What have we learnt? Nothing," she said.

In the face of public uproar over the demolition of three Spanish mission-style buildings at St Heliers in January, Mr Brown promised to raise the bar to protect heritage.

Last night, Mr Brown acknowledged that communication between the various arms of council and agencies on Building 5 could have been better.

He reiterated a determination to do better on heritage, saying the Auckland Plan would place greater emphasis on heritage and a heritage advisory panel was planned.

Last year, the century-old male infirmary ward was saved from demolition when the health board withdrew a demolition consent for it and an appeal against the former Auckland City Council to register it as a category B heritage building.

This followed a two-year battle between the board and Helen Geary with backing from colleagues.

One of them, former Auckland Regional Council chairman Mike Lee, said he was unsure if the decision was a result of ignorance or bureaucratic arrogance.

"Either way it's unacceptable."

Board chief executive Garry Smith said the health body was sympathetic to Building 5's heritage and had considered it for the dialysis unit, but found it was not financially viable.

Mr Smith said no decision had been made about the future of Building 5. Various refurbishment options had been defeated because of the cost of making it earthquake proof and compliant with building standards.