Bayside and Georges River Councils have agreed to continue to share waste services for another 10 to 15 years.
They have agreed to jointly tender for waste services - including domestic and commercial bin collection services - in a 10-year contract with an optional five years extension from 2023 to 2038.
The councils currently share waste services and both agreed at their March meetings that the benefits to sharing resources and costs made the joint bid worthwhile.
Bayside Mayor Joe Awada said: "Joint contracts were in place prior to amalgamation. It was a successful arrangement and this continued cooperation between our Councils will bring significant benefits as resources and costs are shared."
Georges River Mayor Kevin Greene said: "We have already seen how collaborating and working together provides greater benefits for all our residents. Continuing this arrangement will ensure quality waste removal services and savings."
Though the councils will jointly tender for services, each will be responsible for managing their own service requirements.
Each council will have to - either jointly or separately - tender and secure waste collection services by the end of February 2023 when the current waste collection contracts expire.
The new contract will be similar to the existing joint collections contract, which began in 2008 and is due to expire in 2023, that was shared by the former Rockdale, Kogarah and Hurstville Councils.