UPDATED 3:41pm Routine testing has found asbestos at Dunedin Hospital.

Radiology, laboratory, level 4 clinic rooms, theatre and corridor change rooms, and two level 5 corridors all tested positive for the hazardous substance.

Patients are now being diverted through other areas to access ultrasound.

Labour's acting health spokesperson David Clark says the swap results showing asbestos at the hospital are not good enough.

"It is dangerous every day that it's there and not addressed," he said.

"We don't know yet whether it's affected anybody in the past. Asbestos is something that affects people over time."

The Minister of Health says proper steps are being taken regarding the discovery.

Minister of Health Jonathan Coleman says the matter is contained and an active management plan is in place.

He says officials are taking advice and the absolute priority is the safety of the public.

Dr Coleman says experts have been looking at it and the advice is air tests for asbestos have returned negative results.

"They will do some more testing, but the advice we've had is that the risk is very, very low," he said.