The public is being asked to donate to Middlemore Hospital's National Burn Centre to help ease pressure staff are facing following the December 9 Whakaari/White Island eruption.
Fourteen victims remain in hospitals across New Zealand, while 13 have been repatriated to Australian hospitals.
Auckland's Middlemore Hospital is currently treating eight of the severely burned victims, and it is also coordinating the nationwide burns care effort, it said in a statement.
Middlemore Foundation chief executive Sandra Geange said the National Burn Centre team is stretched.
"Middlemore Foundation is asking for money over goods to support this appeal, due to time and resource constraints. This is to speed up the process and provide support as fast as possible where needed."
Patients have suffered "indescribable" injuries and will need to undergo lengthy and painful treatments, Geange added, with many of them having to endure "long periods" of isolation to avoid infections.
"Your compassion and generosity means so much to us here at the Middlemore Foundation and to the caring professionals who staff the National Burn Centre. But most of all, it is the patients and families who benefit most," Geange said.
Online donations can be made here, and bank deposits can be sent to Middlemore Foundation's account 03-0173-0026663-00. The foundation asks that donations are referenced as "burns unit".