"They've squeezed this lemon so hard the efficiency gains are going to be so difficult to find."
She said health boards targeted personnel costs because refilling or not refilling vacancies was an area they could control, unlike external costs.
However, the Lakes DHB is also concerned about the number of staff owed leave. Documents released to the Labour Party under the Official Information Act reveal one in five Lakes DHB staff are owed more than four weeks of leave amounting to $7.99 million.
Public Service Association national secretary Erin Polaczuk said staff were not taking leave and some were working double shifts to cover roster gaps.
Association of Salaried Medical Specialists director Ian Powell said patient safety would be jeopardised by over-stretched staff being placed under increasing pressure.
"This is a short-term solution, if it's a solution at all. If you don't fill positions that need to be filled, you're deferring the problem and increasing the workload on those who need to provide cover."
He said a recent survey by the association had revealed sick staff coming to work when they should be at home, including one doctor who was being treated in the emergency department between seeing her own patients.
Nationwide, DHBs are expected to find $163.5 million in savings this financial year. Most are aiming for multimillion-dollar cutbacks, and four are hoping to reduce net spending by more than $10 million each.
Waikato DHB has a savings target of $43 million - 4.4 per cent of its almost $1 billion budget.
Health Minister Dr Jonathan Coleman said in a statement the health budget was at a record high of $15.9 billion. It was $400 million more than last year and there have been no funding "cuts". The Government's careful management had reduced health board deficits by $150 million since 2008.
