New Zealand's deadly flood emergency continued on Sunday after heavy rainfall hit the country's north island, causing landslides, flash floods and knocking out roads.

Auckland, New Zealand's largest city of 1.6 million people, remained under a state of emergency after it experienced its wettest ever day on Friday, sparking floods that killed four people. 

The focus of the emergency has since moved south, with Waitomo District – located about 220 kilometers from Auckland – declaring a state of emergency late on Saturday.

The nation's weather forecaster, MetService, warned of more severe weather on Sunday and Monday for the north island, including in Auckland, where severe thunderstorms were possible. Intense rainfall could also cause surface and flash flooding, added MetService.

Climate change is causing episodes of heavy rainfall to become more common and more intense, though the impact varies by region. Climate Change Minister James Shaw noted the link to climate change on Saturday when he tweeted his support for those affected by flooding.

On Sunday, police said they were assisting with traffic management and road closures in that region after heavy rainfall "caused numerous slips, flooding and damage to roads."

In nearby Bay of Plenty there was also "widespread flooding," police said, as well as a landslide that had knocked down a house and was threatening neighboring properties.

"Police are asking those in areas experiencing severe weather to ... not attempt to travel on the roads, many of which are currently undriveable," police said.

In hard hit Auckland, flights resumed at Auckland Airport, which had closed domestic and international operations on Friday.

Air New Zealand said the airline's international flights in and out of Auckland would resume from noon on Sunday (2300 GMT on Saturday).

On Saturday, Prime Minister Chris Hipkins, less than a week in office, flew by helicopter over Auckland before touring flood-hit homes. He described the flood impact in the city as "unprecedented" in recent memory.

People made more than 2,000 calls for assistance and 70 evacuations around Auckland – the nation's largest city – due to the inundation, the New Zealand Herald reported Saturday.

On Friday, social media showed firefighters, police and defense force staff rescuing people from flooded homes using ropes and rescue boats.

City rainfall records were broken in the weather event, caused by warm air descending from the tropics, with Auckland Airport logging 249 millimeters in the 24 hours to 9 a.m. on Saturday, beating the 1985 high of 161.8 mm.

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