Wairarapa councils would find it difficult to take on regional-council functions, the latest Morrison Low report on local governance shows.
While a Wairarapa unitary authority would be in a deficit of about $8.6 million, a Wairarapa district council would create a surplus of about $1.6 million.
For a unitary authority, it was assumed the three Wairarapa district councils would amalgamate and take on regional council services in Wairarapa - but the Greater Wellington Regional Council does not record expenditure for Wairarapa specifically.
Costs of the regional council were worked out as a percentage of the total expenditure as budgeted in year one (2012/13) of the council's 2012-22 Long Term Plan.
The report said a unitary authority would suffer from not having the greater purchasing power of the larger Wellington regional council.