St John Ambulance is pulling some ambulances off the road to rein in costs when staff go on leave or call in sick.

In a bulletin on Friday, management advised staff the service needed to "actively manage recalls" of back-up staff in order to curb expenditure.

In response, the Ambulance Association said the "unacceptable" cost-cutting was putting lives at risk.

National secretary Mark Quin said he had already been contacted by worried paramedics in Taranaki and Southland, saying that ambulances had to be parked up over the weekend because they could not be staffed.

"The service is already under significant pressure so this [directive] will only add to it.

"Some patients are waiting five or six hours for an ambulance - that's even with normal crewing and resources on the road.

"If we start dropping resources, that puts on more pressure and raises the risk of people not being able to access an ambulance when they should be."

At bargaining last week, management told the union it had a deficit of $5.5 million for the current financial year, Quin said.

Having earlier agreed to a six percent pay rise - subject to Te Whatu Ora's approval - the service now said it was unable to commit to any pay rise.

St John and Te Whatu Ora have been approached for comment.

Main image (RNZ/Marika Khabazi)