Hospital staff are overworked and services are suffering because vacancies aren't being filled, the Public Service Association says.
Its survey released on Wednesday says some staff aren't able to take breaks or annual leave because of shortages.
Labour's health spokeswoman, Maryan Street, says it's the result of government pressure to cut costs and get budgets under control.
"The result of insufficient and misplaced funding is having a huge impact on frontline services," she said.
"The PSA's survey results show lab tests have been dangerously delayed and physiotherapy hasn't been available to rehabilitate stroke patients."
Ms Street says Health Minister Tony Ryall's instruction for more elective surgery means the needs of other services are being ignored.