MetService has issued a rare Red Heavy Rain Warning for North Otago, Dunedin and coastal Clutha

It warns some areas may get about two months' worth of rain - before the end of Friday.

Dunedin City Council has activated its Civil Defence bunker and is giving out sandbags.

Meteorologist Mmathapelo Makgabutlane says significant flooding and slips are likely.

She says it follows a heavy month of rain, so the ground's already quite sodden.

Orange Warnings still apply to parts of Bay of Plenty and Tairawhiti.

One lane of State Highway 2 is closed is closed between Opotiki and Gisborne - at Otoko Hill - because of a slip.