Only weeks after a long struggle to preserve a century-old cargo shed on Queens Wharf, a new heritage battle is looming at the nearby Britomart precinct.

A panel of independent commissioners has approved plans by the Britomart developer to build a towering hotel in a block of heritage buildings that includes the Union Fish, Police Wharf and Northern Steamship Buildings.

They have dismissed concerns by the Auckland City Council, Auckland Regional Council, Historic Places Trust and heritage campaigner Allan Matson to preserve the "low-rise, heritage-based precinct".

Last night, ARC chairman Mike Lee said he hoped the regional council would lodge an appeal to the Environment Court. The Historic Places Trust is disappointed at the decision and is reviewing its options.

The Auckland City Council, which appointed the commissioners to consider the proposal on its behalf, is obliged to approve the decision even though it opposed the building at the hearing stage.

Mr Lee said once the ARC received city council approval - due to be made tonight - it would decide whether to take further legal action.

"Given it [Britomart] is a special historic precinct, that needs to be respected and pressure from developers for site-specific changes should be resisted," he said.

The commissioners - Greg Hill, Trish Fordyce and Rebecca Skidmore - said any potential effects of the building would be no more than minor.

They agreed with heritage architect Jeremy Salmond, hired by the developer Cooper and Company, that a tall building would not devalue the heritage values of the precinct.

Cooper and Company plans a stepped building made up of two heights - 55.2m and 35.4m, plus 5m for roof structures - to echo the pattern of different heights on Quay St. The allowable building height is 24m for the Quay St site, presently occupied by the Seafarers Building.

Lawyer and resource management expert Richard Brabant said the Auckland City Council had to approve the decision because the commissioners were appointed to make a decision on its behalf. The regional council, he said, could lodge an appeal as a submitter to the private plan change.

Mr Brabant said the agency setting up the Super City had asked councils not to appeal against each other, but it was possible the Auckland Transition Agency would allow the ARC to appeal it because of the issue's importance.