NSW Health is ‘strongly advising’ commuters to wear masks when catching public transport.

It comes after two cases of coronavirus were linked to the growing CBD cluster on a bus from the CBD to the eastern suburbs.

Passengers who caught the X39 bus from Pitt Street opposite Australia Square at 6.08pm on August 20, which arrived at Clovelly Rd and Carrington Road at Randwick at 6.40pm are being urged to self-isolate for 14 days and undergo testing.

One of the positive cases was wearing a mask on the bus but it is not clear if the other was.

“NSW Health strongly advises everyone travelling by public transport to wear a mask at all times,” the department said in a statement.

NSW is using Opal card data to contact commuters.

NSW Health believes as many as 11 passengers were on the bus during the trip.