The death toll from last month's volcanic eruption in New Zealand has risen again, after "highly respected and well-liked" Melbourne man Paul Browitt died in hospital overnight.

Key points: Paul Browitt's daughter Krystal Browitt was also killed in the eruption

Paul Browitt's daughter Krystal Browitt was also killed in the eruption He is the second person to die since being brought to Australia for treatment

He is the second person to die since being brought to Australia for treatment Foreign Minister Marise Payne said other people being treated would remain in hospital for months to come

The Alfred Hospital confirmed Mr Browitt died of injuries he received in the eruption.

His 21-year-old daughter Krystal was confirmed dead in December, while another daughter Stephanie is in a stable condition in hospital.

Mr Browitt's death brings the official death toll from the Whakaari/White Island eruption to 18.

Sixteen people died in New Zealand while Mr Browitt and another man died in hospital in Australia.

Another two people are missing, presumed dead.

Krystal Browitt was on holiday with her family when she was killed. ( Facebook: Krystal Browitt )

Mr Browitt was a longtime staff member at Victoria's State Revenue Office (SRO).

Paul Broderick, the Commissioner of State Revenue, said staff were deeply saddened by news of Mr Browitt's death.

"Paul worked as a highly respected and well-liked senior investigator, and had been with us as a valuable staff member for 36 years," Mr Broderick said.

"We have passed on our thoughts and prayers to Paul's wife Marie, their friends and family. We are all thinking of them at this time."

Karen Batt, the state secretary of the Community and Public Sector Union, told the ABC staff at the SRO were "hurting".

"Paul was a strong advocate and provided great support for his colleagues and was a good union member," Ms Batt said.

"It's very sad for his family and his colleagues at SRO."

The volcano erupted on December 9 with 47 people on the island.

Sixteen Australians have now been confirmed dead in the disaster, including Krystal Browitt, who was the first Australian victim to be formally identified.

Mr Browitt's wife Marie was on board the cruise ship and did not take part in the White Island tour with her husband and daughters.

Friends of the family have been expressing their shock, grief and condolences for Marie Browitt on social media in the last month.

A fundraiser held at a sports club in the family's community raised $32,000 last month.

An online fundraiser has also raised more than $75,000 for the family.

New Zealand authorities called off the search for the missing late last month.

Australian Winona Langford, 17, and New Zealand citizen Hayden Marshall-Inman, 40, are presumed dead.

Rescuers faced the dangerous mission of retrieving tourists and bodies from the island in the days and weeks after the eruption. ( Supplied: Auckland Rescue Helicopter Trust )

Eleven Australian citizens and permanent residents are being treated at specialist burns units in Melbourne and Sydney after being transferred in December.

All of them are in stable conditions, except a person in a critical condition at the Alfred Hospital.

Australian Foreign Minister Marise Payne said she could not go into the details of any other patients, but their treatment would continue for many months to come.

"We've been working very closely with New Zealand, the New South Wales Health Department, the Victorian Health Department — doing an extraordinary job for those who are in hospitals here," she said.

"This is a response from both of our countries to what was a horrific event, and we wish everyone our very, very best."