Australian family missing after eruption

One of the three members of an Adelaide family feared missing after a New Zealand volcano eruption has been found alive.

A Sydney family of four, the Adelaide family of three and a Brisbane mother and daughter were missing after Monday's eruption off the North Island.

Lisa Dallow, 48, was found alive in a New Zealand hospital on Tuesday, but her husband Gavin, 53, and 15-year-old daughter Zoe Hosking are still missing.

Mrs Dallow's family confirmed she had been found in Hamilton Hospital being treated for severe burns.

Three Australians are among five people confirmed dead after the volcanic explosion engulfed tourists on White Island.

More Australians remain missing, while 13 are in hospital being treated for horrific burns and other injuries, the federal government said.

There are serious concerns for the Langford family of North Sydney with Anthony, 51, and Kristine, age unknown, and their children Jesse, 19, and Winona, 17, listed as missing.

Their names are on a website set up by the New Zealand Red Cross to help connect people affected by the catastrophe.

There are still concerns for Ms Dallow's husband and daughter after the trio took a tour from their cruise ship.

Mr Dallow's father, Brian, earlier said they were on the island when the volcano erupted.

"At the moment, we think they might be in hospital," he told the ABC on Tuesday. "We're not sure. We don't really know anything."

The sister of a missing Brisbane woman and her adult daughter has also told the ABC of her rising concern.

Barbara Whitehead has told the broadcaster she's checked with seven New Zealand hospitals trying to find her sister Julie Richards, 47, and niece Jessica Richards, 20.

But there's been no word about the pair, despite other checks with New Zealand police, foreign affairs officials, and the pair's cruise company.

They'd been booked on a tour of the island from the Ovation of the Seas cruise ship, with the mother and her vet student daughter due to return home next weekend.

NZ Red Cross website: redcross.org.nz