Finance Minister Michael Cullen is keen on Auckland evolving towards a single city, but says it is not something the Government can impose on the region.

Speaking at the Herald's Mood of the Boardroom business briefing yesterday, Dr Cullen and National finance spokesman John Key supported the concept of a single city but said local government reform would be difficult.

The drive to make Auckland a world-class city, soaring rates and cross-border squabbles on everything from transport to funding the Auckland Philharmonia Orchestra have re-ignited interest in the super-city concept for Auckland.

Dr Cullen said he would like to see a mechanism under which Auckland could evolve towards a single vision and a single approach, because it did not make sense from a Government perspective to be dealing with five or six local authorities.

"There is always the risk they may veer off in different directions when you just come to the crunch on key issues. It is hard to see how we can create a vision for a world-class city, because what we have got is five non-world-class cities."

Dr Cullen suggested people wait for the final report from the Metro Project on Auckland's future and the conclusion of its team of overseas experts that Auckland needed "major governance reform" if it was to become a world-class city-region.

"The Metro document may provide ways in which we can think about it in a fashion that doesn't frighten everybody."

Dr Cullen said that if the Government tried to impose a solution on Auckland without consensus from the region, "it would fail because the political fightback would be so strong".

Mr Key said local government reform would be "very difficult" to drive.

The Helensville MP said he had three local authorities in his electorate and sometimes it was not possible for them to work together on issues such as roading.

"My personal view is that if we want to progress Auckland fast enough, we need a much more robust decision-making process.

"It is very difficult to achieve that when you have so many stakeholders around the table," he said.

Auckland City Mayor Dick Hubbard said the time had come for the Auckland region to bite the bullet and become one city, saying there would not be the same emotion as in 1989 when all the small borough councils disappeared.

North Shore Mayor George Wood and Waitakere Mayor Bob Harvey are other supporters of a one-city solution to Auckland's woes.

Manukau Mayor Sir Barry Curtis favours a three-city answer.

Mr Hubbard said there was one big stake in the sand and that was the 2011 Rugby World Cup. He had doubts about the ability of the region to prepare for the event without some form of rationalisation.

Former Local Government Commission chairman Grant Kirby this week said ratepayers, taxpayers, the region and the nation deserved better than the current fragmented local government structure in Auckland with 264 elected representatives, more than 5200 staff and a combined annual budget of more than $1.3 billion.

He said Auckland should copy Brisbane, a city of about the same size, and have one mayor, 25 elected representatives and an appropriate number of community boards to give effective local representation and retain local identities.

"Such a structure is practical and pragmatic," Mr Kirby said, "and would finally achieve one funding and service delivery."