Counties Manukau District Health Board is in talks with ACC to recover costs associated with treating the victims of the 2019 Whakaari/White Island volcanic eruption.
The eruption on December 9 saw a number of the injured transferred to the National Burn Centre at Auckland's Middlemore Hospital.
Twenty-one people died in the eruption and 26 were injured, many receiving severe burns.
A report to the DHB's combined committee from April outlined the costs involved in treating the burns victims, which totalled about $11.2 million.
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That included direct patient care, including theatre time and clinical supplies, including skin for grafts, and indirect costs, including diverting non-urgent surgeries.
The DHB's provider arm, which deals with hospital services, now has a deficit of $2.4m, which it says is largely due to treating the Whakaari/White Island victims.
In a statement, a spokesperson for the DHB said it is still in talks with ACC about recovering the costs.
Discussions have been delayed due to level 4 restrictions and the Covid-19 response, the statement said.
The last of the patients from the eruption was discharged from Middlemore Hospital in April.
A spokesperson for ACC confirmed it has been in discussions with the DHB.
Under an agreement with the Ministry of Health ACC provides a fixed annual bulk payment for Public Health Acute Services (PHAS), which equated to about $559m in 2019/20.
But the agreement also includes a special clause which allows for additional payments by ACC in the event of a major burns incident.
"The White Island eruption was the first time this clause has been triggered," the spokesperson said.
Under the terms of the agreement, the additional payment will be made to the Ministry of Health, and then distributed to the DHBs that treated Whakaari/White Island patients, they said.