Bayside Council mayor Joe Awada has written to NSW Premier Gladys Berejiklian, and Minister for Transport Andrew Constance expressing Council's outrage at the decision to privatise the last three bus regions run by the State Transit Authority.
The government is opening Sydney's metropolitan bus contracts to competitive tender.
This includes the last three state-run regions covering the eastern suburbs, Sydney's northwest, north shore and northern beaches.
During the last state election campaign, Ms Berejiklian ruled out more privatisations.
The government is describing the privatising the remaining state-owned bus routes as "franchising".
Councillor Awada warned the State government take heed of the community backlash against this decision.
"Any changes from public ownership to a private model places these vital services at risk of a reduction of service provision," he said.
"These buses provide services for many community members, such as the elderly and disabled, who rely on public buses for their basic transport needs.
"A strong and diverse public transport system is also critical to reducing the number of private vehicles on our already overcrowded road network."
Bayside Council is opposed to the State Government's decision to privatise bus regions 7, 8 and 9, covering Parramatta, Ryde, Epping, the North Shore, the Northern Beaches, the Eastern Suburbs and the City.
Region 9 operates out of Port Botany and privatising this service covering Maroubra and Botany will have a negative impact on all our residents including older community members and those with a disability.