Hamilton's mayor is concerned for the city's future water supply

The city council is urging Auckland's Watercare organisation to develop a new water source and reduce its reliance on the Waikato River.

The Hamilton council is opposing a Watercare application to take a further 150-million-litres per day from the river.

Mayor Paula Southgate says if Auckland gets a 35-year consent to do so, it could lock Hamilton out of a critical resource as demand there also grows.

She says there are businesses wanting to move into the area, as well as big areas of new housing, which need water.