The death toll from the Whakaari/White Island eruption is now at 18.

"Police can confirm a further person died in an Australian hospital last night as a result of injuries suffered in the Whakaari/White Island eruption," says Deputy Commissioner John Tims.

"The death of this person brings the official number of deceased to 18, 16 of whom died in New Zealand and two in Australia."

Two people remain missing following the fatal eruption.

It's presumed the bodies of 40-year-old tour guide Hayden Marshall-Inman and 17-year-old Australian tourist Winona Langford, were washed out to sea.

If anyone comes across a body in the water or along the coast, they are urged to call 111 and wait at the location until emergency services arrive.