SYDNEY -- Heavy rainfall hit New Zealand's north island again on Sunday, causing landslides, flash floods and knocking out roads, with the death toll rising to four after a person who had been missing was confirmed dead.

Battered by rain since Friday, Auckland, New Zealand's largest city of 1.6 million people, remained under a state of emergency. The nation's weather forecaster, MetService, warned of more severe weather on Sunday and Monday for the north island. Intense rainfall could also cause surface and flash flooding, it said.

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

Police confirmed that a man missing after being swept away on Friday in Onewhero, a rural village about 70 kms south of Auckland, had died.

"The most horrific part of it is that we've lost lives," Deputy Prime Minister Carmel Sepuloni told reporters in Auckland.

Climate change is causing episodes of heavy rainfall to become more common and more intense in New Zealand, 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.

Thousands of properties remained without power, while hundreds were without water, authorities said on Sunday.

But Air New Zealand said the airline's international flights in and out of Auckland would resume from noon on Sunday.

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.

(Reporting by Sam McKeith; Editing by Josie Kao)