Aucklanders could face hefty costs for the formation of the new super city.
Prime Minister John Key said the government is cautious on making promises to Aucklanders on costs but it wouldn't have supported consolidation of Auckland unless it believed it provided a better structure.
"It's my view that a consolidated operating structure in Auckland will make for a better, more efficient structure.
"Will that lead to lower costs over time? My view is yes, because by definition you are more efficient. If you are more efficient, you need to spend less on it."
His comments come after Local Government Minister Rodney Hide yesterday announced an examination of local government and its role, including further amalgamations.
Mr Hide told the Local Government New Zealand conference in Auckland that he wasn't out to get widespread amalgamation like the Auckland super city but wanted a discussion about the proper constitutional status of local government, what its function and structure should be and how decision making could be improved.
In his speech Mr Hide said his "Smarter Government -- Stronger Communities" project was about making better decisions. He did not want to see an ad hoc response to calls for amalgamation.
"I am not a fan of amalgamation for amalgamation's sake ... it's not about bigger, it's about better," he said.
He said there needed to be clear criteria against which to consider amalgamations. The project would also consider which roles should be for local and which for central government or up to individual citizens; how local government should be set up; and the best way of setting boundaries to reflect communities.
He expressed concern over the costs being burden on local governments.
"Virtually every government policy affects local government. It seems every new minister's initiative means more costs for local government."
Mr Key said it was a legitimate concern and it has been seen in the past.
"If for instance, central government changes the laws around dogs or prostitution, we impose often costs on local government."
"We need both central and local government to be working together."
Mr Key said there may be further cases of amalgamation around the country, though he prefers the community take the lead.
"In the case of Auckland, we really took the unilateral view out of central government that we would consolidate because this wasn't a new problem. It had manifested itself over a long period of time.
"Around the rest of the country we can also see areas of concern, but are not serious enough that the central government needs to step in. They are much better places if local government and the local communities thought they want that amalgamation."