On Wednesday morning, Hawke's Bay civil defence authorities confirmed the death of a woman in Putorino, a small town north of Napier.
Fire and Emergency NZ (FENZ) were first alerted to the landslip early on Tuesday morning, but were unable to attend due to flooding.
FENZ chief executive Kerry Gregory suggested further deaths from the mammoth storm had been confirmed across the country.
"Overnight there's been reports of further fatalities across the country," he said from a briefing in Auckland on Wednesday morning.
"Our hearts go out to the families of those who have potentially lost their lives last night. It's a really difficult time for New Zealand."
Late on Tuesday, police confirmed a body had been found on the beach on Bay View, just north of Napier.
A police spokeswoman told AAP it had not yet been tied to the effects of Gabrielle, with inquiries ongoing to establish circumstances and identification.
A volunteer firefighter was also trapped in a collapsed house in Muriwai, on Auckland's west coast, for more than 24 hours, with bad weather preventing a search until late on Tuesday.
FENZ spokesman said they would use all the tools at their disposal - including thermal imaging, tracker dogs - to find the man.
"The longer the search goes on for the firefighter, we've got grave concerns for the safety of our firefighter ... (but) no one has given up hope," Mr Monrad said.
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