Whakatane( New Zealand), Dec 11 (AFP) New Zealand police defended delays in recovering bodies from the White Island volcano Wednesday, saying it would be "madness" to rush into a landing on the still-smouldering disaster zone.

Monday's explosion at the popular tourist attraction off the North Island coast resulted in six deaths and authorities believe the remains of eight others listed as missing are still on the island.

A total of 47 day-trippers were on the island when the blast occurred, and many survivors suffered serious burns.

Police Minister Stuart Nash said he understood the frustration of family members who wanted their loved ones' remains returned but said recovery teams had no choice but to wait.

Nash said seismologists had predicted there was a 50 per cent chance of another eruption on the island, which sits semi-submerged 50 kilometres (30 miles) out to sea.

He said there were also poisonous gases pouring from the volcanic vent and the eruption had blanketed the island in a thick layer of acidic ash.

"It would be madness for us to send men and women across to White Island in a situation that was not safe for them," he told Radio New Zealand.

"We have a responsibility to New Zealand police staff to ensure any situation we put them in is safe."

Nash said reconnaissance flights had determined soon after survivors fled the initial blast that there was no one alive on the island.

Police want to deploy drones to measure toxic gas levels in the island's atmosphere and determine whether it is safe to return, but windy conditions have so far prevented them from being flown.

With weather expected to deteriorate on Thursday, pressure is building to start the recovery operation.

"We're assessing all factors every two or three hours to see if we can go," superintendent Bruce Bird told reporters.

Visitors to the island, which is marketed as an adventurous day trip, included a group of more than 30 from a Royal Caribbean cruise ship, the Ovation of the Seas, which left Sydney on a 12-day voyage last week.

The ship had delayed its departure from nearby Tauranga in the wake of the disaster but set off for Wellington early Wednesday morning.

"A team will remain onsite in Tauranga and all hospital locations to ensure those affected by Monday's incident are taken care of in terms of medical help, counselling, accommodations, and transport," the company said in a statement.

"Our priority continues to be to ensure that all guests and crew impacted are well taken care."

Among those caught on the island during the sudden blast were tourists from Australia, the United States, Britain, China, Germany and Malaysia, as well as local tour guides.

The death toll reached six late Tuesday when an injured person died in an Auckland hospital and Nash said it could rise further.

"There are still some very, very seriously injured people in hospital. We wish them the best but we're not out of the woods yet, of that there's no doubt," he said.

At least 26 survivors are being treated for severe burns and Nash said some were so badly injured their identity was still not known.

"My understanding is that nine are still in a critical condition, they cannot speak in any way shape or form or communicate," he said.

He said authorities were being cautious about publicly releasing victims' details to avoid any mistakes.(AFP)

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