He drew some old friends to the launch, including Dame Jenny Gibbs, retiring Act MP Sir Roger Douglas, former Labour Cabinet minister Michael Bassett and former National MP Pat Hunt, as well as Act leader Don Brash.
Also on hand was his right-hand man from mayoral campaigns, Brian Nicole, and long-time Act strategist Australian Ian Kortlang.
He reminded his audience of his earliest taste of politics - as a 14-year-old boy being fostered by Alan McCready, a former National Party Police Minister.
Mr McCready had taken the young Banksie to Parliament, sat the boy in his seat and told him, "One day you too could be an MP."
Mr Banks, whose parents both spent time in prison, went on to become a National Party Minister of Police and later Auckland City Mayor.
He said New Zealand had been generous to him in the opportunities it had offered him, and he wanted the same opportunities for young people today.
Act got 1.5 per cent in Saturday's Herald-DigiPoll survey, a result that would see the party with two seats if it retains Epsom, but none if it doesn't.