Wairarapa councils have significantly underestimated the cost of becoming a unitary authority, says Greater Wellington Regional Council chairwoman Fran Wilde.
Councils in the Wellington region are considering options for the future governance of the region, and Wairarapa councils have agreed on a preferred option of a unitary authority.
Leaders disputed the amount subsidised by Greater Wellington this week when they argued Wairarapa can afford to become a unitary authority.
Figures provided to then-Carterton Mayor Gary McPhee in 2008 estimated the subsidy to be about $4.5 million, but figures provided in a report commissioned by the three Wairarapa district councils estimated this figure to be $11.2 million, and the mayors questioned why the figure was so high.
Ms Wilde said the report has a host of inaccuracies and the spend could not easily be reduced.