Residents in Waihi are being asked to conserve water at the moment to relieve pressure on the local water treatment plant, which is working overtime.

The heavy rainfall has caused processing of drinking water in Waihi to take longer than usual.

Water quality at the tap is unaffected, but output is lower because of the extra time needed to remove silt and debris, reports Hauraki District Council.

At the current rate of usage the water treatment plant will not keep up with the town's demand so Waihi and Waikino residents are being asked to conserve water for the next few days.

"This is a temporary problem and things are expected to be back to normal within the next 24 to 48 hours. In the meantime we are seeking the cooperation of the community to prevent serious shortages by conserving as much water as possible now," says Hauraki District Council group manager engineering services Adrian de Laborde.

MetService reports a trough is forecast to cross central New Zealand today, while a deep low moves rapidly southeast across the northern North Island.

These systems are forecast to bring further bursts of heavy rain, with possible thunderstorms and gales to the far north and east of the North Island.

Brief heavy rain and isolated thunderstorms are expected over northern and central parts of the North Island for a time today. The heaviest falls here are likely in eastern Bay of Plenty where another 50 to 80mm of rain may accumulate by this evening.

Follow the HDC Facebook page for any updates on the water situation in Waihi.