Transport Workers' Union (TWU) NSW State Secretary Richard Olsen said bus drivers at Smithfield stood up for their right to a safe workplace and "they've won."
Bus services will resume from the Transit Systems depot in Smithfield on Friday at 3.30pm after the operator agreed to rapid antigen testing of all drivers starting on September 13.
It caused a significant number of bus services in Liverpool, Fairfield, Merrylands and Parramatta to be cancelled.
"Fortunately, these drivers and the TWU were able to get Transit Systems to agree to implement rapid antigen testing in the Smithfield depot, but it should never have come to this," Mr Olsen said.
"The TWU apologises for any disruption caused by the depot being closed, and thanks the community for their support of drivers in their fight for a safe workplace.
"The TWU has been calling on the NSW Government to introduce rapid antigen testing across the entire network for months - and until now those calls have fallen on deaf ears.
"The NSW Government can't keep leaving this to the private operators to deal with - they need to fund rapid antigen testing in every bus depot across Sydney."
On Thursday, a Transport for NSW spokesperson said the safety of staff and customers is their "number one priority".
"Transport for NSW is already in the process of trialling Rapid Antigen Testing across key work locations of the network," the spokesperson said.
"Transport for NSW will continue to follow all Health advice and the COVIDSafe Transport Plan remains in place across the network, including enhanced cleaning.
"The use of RAT within Transport is intended as an extra measure to protect staff and customer and to ensure the continuation of services. It is not related to requirements under the current Public Health Orders."