Cyclone Gabrielle has moved away from New Zealand, although heavy rain and flooding continued on Thursday across the North Island. At least six people have died, while thousands can't be contacted.

Gabrielle swept across New Zealand's north coast earlier this week, seriously damaging roads, bridges and telecommunications infrastructure.

The fatalities include a child and two volunteer firefighters.

The country remains in a state of emergency. Thousands of residents have lost their homes or become stranded. More than 3,500 have been reported to police as out of contact.

Prime Minister Chris Hipkins says he realizes the pain being felt by New Zealanders after weeks of severe weather. He promised to invest in resilient infrastructure that can stand up to extreme weather events.

Australia has committed to provide assistance requested by New Zealand.