Ms Hancock said representations on the de-amalgamation proposal could be made by a council or elector affected by the proposal from yesterday, January 9, until Friday January 31.

"If you support or object to the proposal proceeding to the Boundaries Commission you make may submissions or comments to my office," Ms Shellley said.

The merger of Cootamundra and Gundagai shire councils was forced on the region by the Baird government in 2016.

Ms Hancock issued a statement in November saying she had "listened carefully to the views of the community, the councils and local members".

After she has considered the submissions made this month, she would decide whether to refer the demerger proposals to the Local Government Boundaries Commission, an independent statutory authority, for "examination and report".

Last year, Ms Hancock received a petition signed by around 12 per cent of enrolled voters in the region.

"By law I am then required to consider all submissions before referring the proposals to the Commision, for examination and report," she said.

Ms Hancock said a proposal to demerge the Snowy Valleys Council could also be referred to the Commission.

Opposition to the mergers has been particularly strong in Gundagai and Tumut.

In Gundagai a "Gundagai Council in Exile" (CGIE) was formed and was the driving force behind the petition.

MP for Cootamundra, Steph Cooke, last year welcomed the announcement as a "giant step forward" for the Gundagai community.

Mayor Abb McAlister, an opponent of amalgamation in 2016, also welcomed the review.

He said the process had been unanimously backed by other councils at NSW local government conferences.