A woman has been arrested after gas supplies were allegedly sabotaged at two Sydney hospitals.

Sutherland hospital in southern Sydney lost medical gases on Tuesday morning, requiring them to switch to portable oxygen and air as part of their contingency plans, the New South Wales health minister, Ryan Park, said in a statement.

Park said “the cause of the loss of gases is alleged to be deliberate sabotage”.

“A woman is now in police custody,” the minister said. “To [allegedly] do this is beyond serious. It could have been catastrophic.”

NSW police said they received reports of “alleged vandalism at two hospitals in Caringbah”. It’s understood that the other facility was a nearby private hospital.

Police alleged a 42-year-old woman entered the grounds of a hospital on Kareena Road at about 12.20am on Tuesday and “cut both the water and gas mains, before activating fire hoses”.

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They further alleged that at about 1.30am “the woman entered the grounds of another hospital on Kareena Road … and allegedly switched off the gas main”.

She was arrested in Miranda at about 4am on Tuesday for breach of bail, NSW police said.

The health minister said gas systems were restored by South Eastern Sydney local health district and Sutherland hospital teams “within approximately two hours”.

“I want to assure the community there was no impact to patient care and that the system has returned to operating as per normal,” Park said.

“Access to gas systems in NSW public hospitals is restricted. We will review the incident to see what improvements can be implemented.”

Park told reporters the woman allegedly scaled a wall at Sutherland hospital and gained access to a restricted area.