A third Sydney hospital has been probed for exposure to coronavirus after it was revealed one of New South Wales’ 26 cases was a worker there.

NSW Chief Medical Officer Dr Kerry Chant confirmed on Friday a health care professional at Canterbury Hospital, in south-western Sydney, had tested positive for the potentially deadly virus.

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She said the female staff member worked on February 25 and March 3 while infected with coronavirus.

She didn’t test positive for the virus until March 4.

NSW Health Minister Brad Hazzard (left) and NSW Chief Health Officer Dr Kerry Chant. Credit: JOEL CARRETT / AAPIMAGE

Chant said 28 staff members, including 13 close contacts and 15 casual contacts, have been identified by health authorities.

A further three patients were also in contact with the health care worker.

They have all been given the “appropriate advice around isolation”, though she did not elaborate on what that was per case.

File Image: A third Sydney hospital has been probed for exposure to coronavirus after it was revealed one of New South Wales’ 26 cases was a worker. Credit: Andrew Merry / Getty Images

It comes a day after two other hospitals, Liverpool Hospital and Ryde Hospital, had dozens of staffers self-isolated.

Twenty-three staff members from Liverpool Hospital and 61 from Ryde Hospital have been placed into self-isolation over fears they interacted with an infected person.

Sixty-one patients between those two hospitals have also been identified and are being monitored closely.

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NSW Chief Medical Officer Dr Kerry Chant said measures were in place to ensure hospitals were adequately staffed.

“I want to reassure the public that we have several mitigation strategies in place to backfill any absent staff with other health workers to ensure continuity of service in our hospitals,” she said.

The total number of cases in NSW is 26, with more than 50 cases reported nationwide.