Greater Wellington Regional Council chairwoman Fran Wilde believes Wairarapa would have to overcome "major challenges" to stand on its own as a unitary authority.
This week the regional council will decide whether or not to lodge an application for a single council with local boards for the Wellington region, including Wairarapa.
If successful, this would create a new Wellington council, replacing nine existing councils.
The council would have 22 members, a mayor elected at large and councillors elected on a ward basis.
There would be eight local boards, with up to nine members each.