The four Victorian dioceses of Sandhurst, Ballarat, Melbourne and Sale will unite to form one common social services organisation from January 1.

Bishop of Sandhurst Shane Mackinlay said the change had the potential to enhance services in all the organisations, by combining their strengths.

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Bishop Mackinlay pointed to social housing as an area of need in Bendigo, that he hoped to see bolstered by the merger.

Together the organisations could draw on each others' strengths and increase visibility and influence, Bishop Mackinlay said.

He said a single body would also be able to work more effectively with government.

"It's allowing the Catholic church in this diocese to more effectively continue the mission of the church in support of those in need in our community ...to advocate for services that help address their needs, especially with government," Bishop Mackinlay said.

"It'll have a both greater visibility in terms of its size, but also greater credibility because of the sheer breadth of engagement it can draw on across the state."

The new body will be known as CatholicCare Victoria.

Bishop Mackinlay said the merger had happened at a time when CatholicCare Sandhurst would have needed to change its governance structure regardless, to meet new government requirements.

He said there would be no immediate changes to the services offered across the state, but over time he expected more opportunities for integration.

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