The decision to join was made at the board meeting held in Mudgee on December 9.

Orana JO chair, councillor Craig Davies welcomed the "capital of our region" and said their formal inclusion would help the JO work collaboratively with the state government to plan, prioritise and deliver projects on a regional scale to the Orana region.

"Dubbo are now on board which is terrific, it's good to have them on board because they are the capital of our region, and they bring with them size and capacity that our JO has been lacking," he said.

"It's an opportunity now for the other six councils who have been in this organisation to come together with Dubbo and form a really viable JO that can move ahead collectively for the betterment of the whole region."

Councillor Davies said drought and water is the major focus of Orana JO's unified activities over the next year, including the proposal of a pipeline from Burrendong Dam out west.

"We've got a couple of projects we're working with already, we've got one with CSU at the moment ... and the other one probably that will end up in our lap should be the pipeline project," he said.

"It is a very natural fit for a JO as it basically covers the footprint of our JO.

"It goes out as far as Cobar, and whilst Cobar are not part of our JO, were more than happy to be taking a leading role in all this.

"Bourke have also indicated their interest in having it extended out to them ... to give them certainty into their future.

"So there are many councils in the JO that will benefit from this, so it's a good project to have under our belt."

In March last year, Dubbo decided not to join forces with Gilgandra, Narromine, Warren, Bogan, Warrumbungle and Mid Western Regional councils.

At the time, Dubbo Regional Council was concerned about the cost of joining the organisation. However last month, Dubbo mayor Ben Shields had pushed for Dubbo to reconsider.