Auckland City Mayor John Banks last night promised not to sell council shares in Auckland Airport or any more pensioner houses if he becomes the first mayor of the Super City.

Mr Banks, who sold Auckland City's stock of pensioner houses and half its airport shares to pay down a "mountain of debt" in his first term, said pensioners living in houses owned by other councils across the region could rest easy.

About 1200 pensioner council houses for low-income older people are owned by Manukau, North Shore, Franklin and Papakura councils.

The promise to retain other councils' pensioner housing was made at the first head-to-head debate between Mr Banks and the other heavyweight mayoral contender, Len Brown of Manukau, at a function organised by law firm Chapman Tripp.

Asked about the role of affordable housing in the Super City, Mr Banks said it was important but it should be funded by taxpayers, not ratepayers.

Sitting - rather appropriately - on the left of Mr Banks, Mr Brown said he was encouraged by the message but urged people to weigh it against Mr Banks' history and whether it would be delivered.

"We [Manukau] never sold our housing for the elderly, the 524 units. We held them because we saw the benefit of those in our community who were older and have poor incomes."

Mr Brown said Manukau gave land rather than money to leverage more housing by the private sector or other agencies.

Housing was the only social question raised at the debate, attended by about 130 lawyers and guests from the business community who, in the words of Chapman Tripp chief executive Alastair Carruthers, came to hear two of the region's "most distinguished and hard-working citizens".

Both men were firm when answering a question from former Auckland Airport boss Don Huse about selling Auckland City and Manukau's shares in Auckland Airport to "reallocate these funds to new infrastructure for the new Super City".

Mr Banks said he was not going to dismantle the strategic asset base of Auckland by selling the shares, and Mr Brown said the shares had been extremely beneficial and welcomed by the community for a long time.

Both candidates spoke of using infrastructure bonds to fund large projects, such as a central city rail loop and rail to the airport but, surprisingly, the left-leaning Mr Brown raised the possibility of public-private partnerships, tolling and other types of user charges to pay the cost.

There was little to separate the two mayors on their visions for Auckland, but Mr Banks insisted the election was going to be about leadership.

"Stable leadership that is able to make the hard daily decisions based on 45 years of successful business in this city and 30 years of public service."

Mr Banks also used the occasion to announce a policy for transparency and accountability to include a mayor and chairs' interest register (councils already have "related party disclosure" for the mayor and councillors), issuing mayoral and councillor expenses online every three months and looking at webcasting of council and committee meetings.

Mr Brown said his three platforms for the Auckland Council would be economic development, environmental sustainability and cohesive communities. He pledged to be a "uniter" and make Auckland "the eco-city of this planet".

Why I should be the mayor

Len Brown:

"Every day I wake up and, for one thing, I'm thankful I do wake up. But secondly, I have the greatest job in the world and it's a job that enables me to make a difference, to really change people's lives, to deliver change, new direction and positive growth in the community. I can sort of perform little miracles around our place. When the change occurred I wondered whether I could shift this position to the community that has raised me since I was 7. I have very quickly found that passion. It has been an extraordinary journey thus far and the opportunity to deliver something by the way of step change and extraordinary redirection of Auckland and taking up of its potential, a marrying of our business dynamic with our community aroha and love is something I believe is an extraordinary opportunity, and I would like to take that opportunity."

John Banks

At age 18, I decided that I would balance the family ledger by joining the police. The Auckland police told me in no uncertain terms that I was a lowlife son of two shitbags and there was no place for me in the New Zealand police. Twenty-five years later, I became the Minister of Police. I'm doing this to balance the family ledger.