Waikato Regional Council says more rain than expected has fallen on the Coromandel peninsula, causing concern over the level of the Ohinemuri River.
Around 300mm has fallen in the catchment in the last 12 hours.
As a precautionary measure, duty emergency management officer Adam Munro says flood gates at Paeroa may be used, which will close State Highway 26 at Paeroa.
SH2 through the Karangahake Gorge is closed due to flooding.
Earlier concern about the Kauaeranga River has passed with the level dropping.