An Australian teenager and a New Zealand tour guide are the two people whose bodies have not been found after last week's volcanic eruption in New Zealand that killed 18 people.

New Zealand police said the bodies of Winona Langford of Sydney and New Zealander Hayden Marshall-Inman have yet to be accounted for.

Authorities believe both bodies are in the waters around White Island, but harsh conditions on Tuesday forced an abandonment of the search for a second straight day.

Inclement weather struck the Bay of Plenty, where White Island is located, and a water-based search has been ruled out due to the forecast of storms.

Winona's parents, Anthony and Kristine Langford, died in the eruption, while her brother, Jesse Langford, survived with severe burns and is being treated in a Sydney hospital.

New Zealand volcano: Eruption in photos Show all 20 1 /20 New Zealand volcano: Eruption in photos New Zealand volcano: Eruption in photos Smoke from the volcanic eruption of Whakaari, also known as White Island. New Zealand police said the blast had left five people dead, but that number will now rise to include those people who were still on the island when it erupted allessandrokauffmann via Reuters New Zealand volcano: Eruption in photos Emergency services attend to an injured person TVNZ via Reuters New Zealand volcano: Eruption in photos Thick smoke from the volcanic eruption SCH via Reuters New Zealand volcano: Eruption in photos The volcano on New Zealand's White Island spewing steam and ash moments after it erupted Michael Schade/AFP via Getty New Zealand volcano: Eruption in photos White Island Tour operators rescuing people minutes after the volcano erupted Michael Schade/AFP via Getty New Zealand volcano: Eruption in photos Thick smoke from the volcanic eruption from a distance of a vessel SCH via Reuters New Zealand volcano: Eruption in photos An aerial photo shows White Island after its volcanic eruption New Zealand Herald via AP New Zealand volcano: Eruption in photos An aerial view shows smoke bellowing above the crater of Whakaari GNS Science via Reuters New Zealand volcano: Eruption in photos Emergency services attend to an injured person arriving at the Whakatane Airfield New Zealand Herald via AP New Zealand volcano: Eruption in photos This handout photograph courtesy of Michael Schade shows the volcano on New Zealand's White Island spewing steam and ash minutes following an eruption on December 9, 2019. - New Zealand police said at least one person was killed and more fatalities were likely, after an island volcano popular with tourists erupted on December 9 leaving dozens stranded. (Photo by Handout / Michael Schade / AFP) / RESTRICTED TO EDITORIAL USE - MANDATORY CREDIT "AFP PHOTO / MICHAEL SCHADE" - NO MARKETING NO ADVERTISING CAMPAIGNS - DISTRIBUTED AS A SERVICE TO CLIENTS == NO ARCHIVE (Photo by HANDOUT/Michael Schade/AFP via Getty Images) HANDOUT Michael Schade/AFP via Getty New Zealand volcano: Eruption in photos A wreckage of a helicopter amid ash minutes after the volcano on New Zealand's White Island erupted Michael Schade/AFP via Getty New Zealand volcano: Eruption in photos SCH via Reuters SCH via Reuters New Zealand volcano: Eruption in photos This image released by GNS Science, shows plumes of smoke from a volcanic eruption on White Island, seen from Whakatane, New Zealand Monday, Dec. 9, 2019. A volcano erupted Monday on a small New Zealand island frequented by tourists, and a number of people were missing and injured after the eruption. (GNS Science via AP) GNS Science via AP New Zealand volcano: Eruption in photos An aerial view shows smoke bellowing above the crater of Whakaari, also known as White Island, volcano as it erupts in New Zealand, December 9, 2019, in this image obtained via social media. GNS Science via REUTERS ATTENTION EDITORS - THIS IMAGE HAS BEEN SUPPLIED BY A THIRD PARTY. MANDATORY CREDIT. NO RESALES. NO ARCHIVES. WATERMARKS AT SOURCE. GNS SCIENCE GNS Science via Reuters New Zealand volcano: Eruption in photos epa08056782 A handout photo made available by the New Zealand Police shows White Island (Whakaari) volcano, as it erupts, in the Bay of Plenty, New Zealand, 09 December 2019. According to police, at least five people have died in the volcanic erruption at around 2:11 pm local time on 09 December. The island is located around 40km offshore of the Bay of Plenty. EPA/NEW ZEALAND POLICE HANDOUT BEST QUALITY AVAILABLE MANDATORY CREDIT HANDOUT EDITORIAL USE ONLY/NO SALES NEW ZEALAND POLICE HANDOUT EPA New Zealand volcano: Eruption in photos An aerial view shows hikers walking on the crater rim of Whakaari, also known as White Island, shortly before the volcano erupted GNS Science via Reuters New Zealand volcano: Eruption in photos Emergency services at Whakatane Airport Getty Images New Zealand volcano: Eruption in photos A rescue helicopter arrving at the airport Getty Images New Zealand volcano: Eruption in photos White Island (Whakaari) volcano, as it erupts Michael Schade/EPA New Zealand volcano: Eruption in photos White Island (Whakaari) volcano, shortly before erupting Michael Schade/EPA

In a previously released statement from the Langford family, Anthony and Kristine were described as “loving parents”.

“They will be greatly missed by all who knew them,” the statement said.

New Zealand police also released the names of three more people who died in the eruption: Australians Richard Elzer and Julie Richards and Sydney-based US citizen Barbara Hollander.

Of the 47 people on White Island on 9 December when it erupted, 24 were Australian citizens and four others were residents of Australia.

Australia's foreign minister Marise Payne said the trauma had taken a toll on the families of the victims.

“I don't think any one of us can begin to imagine what those families are facing in the coming weeks and months,” an emotional Ms Payne told reporters. “Here in places like Auckland, in Sydney, we're surrounded by Christmas and celebration, but they face tragedy and devastation.”

“Our hearts and thoughts are with them every step of the way,” she added.

Military specialists recovered six bodies last Friday from White Island, which remains at risk of erupting again.

Scientists have warned that the island, which is the exposed tip of a mostly undersea volcano, is highly volatile, and has been venting steam and mud regularly.

Survivors are being treated in hospitals across New Zealand and Australia.

Specialist medical teams from Australia, Britain and the US have assisted in New Zealand.