Many parts of the upper North Island have been battered by heavy rain overnight

The Gisborne District and eastern Bay of Plenty have been receiving the heaviest falls, with high river levels and reports of flooding.

Meanwhile, in the South Island, work is underway to enable limited access through Otago's only direct link to the West Coast, from today.

Officials want to partially re-open a single lane of traffic for light vehicles to be escorted through at set times through State Highway 6.

Subject to a final assessment at 9am today, two escorted convoys for light vehicles will run at noon and 4.30pm.