The official death toll from a volcanic eruption in New Zealand in December rose to 20 on Thursday after police there announced that the last two missing victims have been officially declared dead.

The bodies of New Zealand tour guide Hayden Marshall-Inman and Australian tourist Winona Langford were never recovered, following the eruption the volcano off North Island on Dec. 9.

(White Island Volcano)[Getty/Kyodo]

According to a statement by Police Deputy Commissioner John Tims, the chief coroner has ruled that both people died on White Island, also known by its indigenous Maori name Whakaari.

A total of 47 mostly tourists -- 24 Australians, nine Americans, five New Zealanders, four Germans, two Chinese, two Britons and one Malaysian -- were there when it suddenly erupted.

Of those who died, 14 were from Australia, four from the United States and two from New Zealand. The others were injured, some with severe burns.

White Island, roughly 50 kilometers off the coast of North Island, is New Zealand's most active cone volcano and was a popular tourist destination, with over 10,000 people visiting each year through daily tours operated by a private company.