The massive bill for rebuilding Christchurch will not put the Government off spending more money on Auckland, Prime Minister John Key says.

Around 400 civic, political, community and business leaders gathered at the Auckland Unleashed summit at the Aotea Centre today.

"Even though we are all proud Aucklanders, we know Auckland can be better," Mr Key said.

The cost of rebuilding Christchurch after the devastating February 22 quake cast a shadow over most of the speakers' addresses, including the Prime Minister's.

Mr Key said there were three ways the Government could raise the revenue needed to repair Christchurch: either by borrowing, through a levy, or by trimming expenditure - which was the Government's preferred option.

However, he said this did not mean they won't be spending more in Auckland and the planned investments will still go ahead.

Mr Key said as the "flagship city", Auckland is important for New Zealand.

"This is the place where a lot of revenue is generated and paid to us," he said.

The day-long mayoral forum marked the release of the discussion document for the Auckland Plan, also called the spatial plan, which will be a guide for development and growth in the city for the next 30 years.

Mayor Len Brown opened the event, speaking of his vision for the city.

"I want us to be the world's most liveable city.

"To transform Auckland's economy, to boost its quality of life, to turn it into the world's most liveable city, we need to reach out to all 1.4 million people of this place for guidance, advice, encouragement and involvement," he said.

Mr Brown said the city should be proud of its heritage and must have a "world class transport system".

Don McKinnon, the former Commonwealth Secretary General and current director of the Auckland Museum, said Auckland needs to be better marketed to the world as a destination in its own right.

"We have to see Auckland as a destination not a transit point to Rotorua, Queenstown or anywhere else," he said.

Dr Arthur Grimes, the chairman of the Reserve Bank Board, said Auckland does not compete against other New Zealand cities, rather it is up against Sydney, Brisbane and Melbourne.

"Why set up a firm in Auckland? Where do skilled people want to live? Auckland is just one of many places," he said.

Mr Grimes said Auckland needs to incorporate Tauranga, Hamilton and Whangarei in its future.

John Rae, chairman of the New Zealand Council for Infrastructure Development, said investment in infrastructure over past 30 years has been reactive, not proactive.

"As a consequence we are currently backfilling decades of underinvestment in our electricity, road, rail , telecommunications and water networks," he said.

"[Investment] has been seen as a cost rather than an investment.

"The tragic events in Christchurch and Japan indelibly underscore the criticality of having resilient water, energy, telecommunications and transport infrastructure as the very foundation upon which human existence in our modern society is based."

Keynote speaker Stephen Loosley the chairman of the Committee for Sydney, said the forming of the super city gave Auckland a "significant advantage".

"No one doubts Boris Johnson speaks for London, no one doubts Michael Bloomberg speaks for New York. We now have a situation where Len Brown speaks for Auckland. That is a significant advantage," he said. "No one effectively speaks for greater Sydney."

Mr Loosley said a city needs common purpose, confidence and creativity to be a great international city.

"Auckland needs to ask itself - do you want to play in the game? How will you want to play it, and where do you want to place?"