Sydney commuters are being told to "brace for chaos" across the city's bus network as the state suffers a bus driver shortage.
Unions have said operators have been forced to cancel thousands of services as transport authorities insist the situation is only temporary.
A Transport for NSW spokeswoman said the cancellations were due to operators removing less reliable services from the timetable so they did not cancel services ad hoc.
"Several bus operators across Greater Sydney are making temporary service adjustments to deal with unprecedented driver shortages across the industry," the spokeswoman said on Sunday.
The cancellations cover regions north, northwest and south of downtown Sydney, including the northern beaches and eastern suburbs.
While the union says another region southwest of the city, encompassing the inner west, will also be affected, Transport for NSW said those changes had been made in December.
The Rail, Tram and Bus Union (RTBU) is blaming the privatisation of the state network, with industry conditions struggling to entice and retain drivers.
"Commuters should brace for chaos at our bus stops from Monday as the NSW government axes thousands of trips in an attempt to deal with the fallout of its bus privatisation," Mr Grech said on Sunday.
He urged commuters not to take their frustrations out on drivers, saying the state government was to blame for the network's poor state.
Premier Dominic Perrottet blamed frequent union actions on the driver shortage despite the union not holding any actions on Monday.
Transport Minister David Elliott was contacted for comment.
