Wellington's leadership is up in the air with long-serving incumbent Kerry Prendergast ahead of her nearest challenger by a mere 40 votes and many ballots still to be counted.

The nation's capital was besieged yesterday: under fire from some of its neighbours and watching its historic power slip away to Len Brown's new Auckland Supercity.

Prendergast's road-building policy lost votes to Green rival Celia Wade-Brown: When the result was announced at the council chambers last night, Prendergast turned on her heel and stepped into the lift before Wade-Brown could shake her hand.

About 900 special votes are still to be counted and the outcome will not be announced until tomorrow at the earliest. Neither candidate would rule out seeking a judicial recount if the results went against them.

The mayor's enthusiasm for some form of greater Wellington council has also infuriated some neighbouring communities. The region's nine mayors have been shown a draft of a $150,000 ratepayer-funded report but have delayed finalising it until after the election. The Herald on Sunday understands it stops short of full amalgamation of the councils but proposes extensive mergers of services and infrastructure. Local Government Minister Rodney Hide said he expected the reality of the Auckland Supercity to spark debate in other areas about fresh mergers. The Government's review of local councils might open the door to further mergers but none were planned.

Newly elected Carterton mayor Ron Mark, a former NZ First MP, said he and his fellow Wairarapa mayors, Masterton's Garry Daniell and South Wairarapa's Adrienne Staples, would fight any attempt to subsume them into Wellington.

"My message to Kerry Prendergast is: We're not interested," he said.

"What's not helped is that Kerry Prendergast as mayor of Wellington has been quite derisive and derogatory about Carterton.

"She said a mayor of Carterton would never get a meeting with the Prime Minister. Well, I've since met with John Key and he agrees with me. Kerry's on her own."

Prendergast said she was surprised by Mark's attack, saying she had never supported an Auckland-style Supercity but change was "inevitable" because of the Government's review of local councils.

Kapiti Coast Mayor Jenny Rowan held on for a second term but was undecided on whether her area should be part of a Supercity.

Prendergast faces dealing with several new Wellington region mayors: As well as Ron Mark, Hutt City has a new mayor with Ray Wallace deposing David Ogden. And in Porirua, rank outsider Nick Leggett beat deputy mayor Litea Ah Hoi to succeed Jenny Brash, who retired at the election.