The MetService says there is a possibility of a short burst of heavy rain over the Coromandel Peninsular and Kaimai Ranges on Saturday.
It says up to 100 mm could fall at some stage in a short space of time as part of a heavy rain forecast.
Waikato Regional Council says people need to watch for rising river levels and slips and that farmers should move stock to higher ground if necessary.
It says rivers in the eastern part of Waikato are already high and more heavy rain over the weekend will place further pressure on river systems.
