The country's biggest hospital faces cost-cutting measures to rein in a potential $12 million budget shortfall.
The Auckland District Health Board has confirmed some areas of the organisation were told to control overspending, but it didn't expect to fall into deficit.
An internal email called for urgent change to address significant losses in theatre costs, and children and older people's services, Radio NZ reported.
The email, sent a few weeks ago to senior staff, was leaked to Radio NZ.
ADHB chief executive Ailsa Claire said she did not expect an operating deficit at the end of the financial year.
"However, as is always the case, some services have overspent their budgets and some have underspent," she said.
Some areas of the hospital were being told to cut costs to control over-spending.
"There have been overspends in some parts of the organisation and we need to sort that out," she said.
"We must deal with overspends because we cannot always rely on other areas under-spending to balance things out."
Auckland DHB has an annual budget of almost $2 billion, or $38 million per week.
The DHB operates the country's largest public hospital, Auckland City Hospital.
Dealing with over and under-spending is a constant challenge with health budgets, Claire said.
"The challenge to balance finances is a constant for all DHBs," she said.
"It is nothing new and is discussed at every board meeting."
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