Local government and public services secretary Alun Davies on Tuesday announced next steps following a consultation on the green paper on local government reform.
This had put forward three options for council reorganisation: voluntary mergers; phased mergers; and comprehensive mergers at the earliest opportunity.
Davies said: “There was an appetite amongst local government to work together to progress voluntary mergers and increase and improve regional working.”
He added that he would introduce a local government bill to the Welsh Assembly “at the earliest opportunity” and also establish an independent working group to take forward a shared approach in conjunction with the Welsh Local Government Association.
The working group will be chaired by Derek Vaughan, who has been a member of the European Parliament for Wales since 2009. He was previously a councillor, leading Neath Port Talbot County Council as well as serving as leader of the WLGA.
Davies added: “For a great deal of time many groups and individuals, including local government leaders, told me that the current system and structures for local government were not sustainable.
“I want to work with local government on a shared vision for the future, and to jointly develop solutions to the challenges they face. Those challenges – about how we maintain progressive public services in the context of long-term austerity – are not going to go away.”
WLGA leader Debbie Wilcox said: “We are supportive of any councils who desire to merge voluntarily and are committed to working collaboratively to deliver services, and this group will consider the potential support that might be available should councils choose to merge.
“The key point is that sustainability is not achieved by structures but resources and service transformation.”
Previous efforts to streamline local government structures in Wales have struggled.
A proposal to more than halve the 22 Welsh councils was met with opposition from the sector and Welsh Assembly members, forcing Cardiff to rethink its plans.