Mr Brownlee said the sponsorship deal was not related "in any way" to the 2011 Government decision to underwrite the insurer.
He said insurance company IAG, which bought AMI earlier this month, recognised the value of continuing to support Christchurch.
"IAG recognises the symbolism of supporting a venue identified as being important for the morale of the people of Canterbury, and I thank them for that."
IAG was cleared by the Commerce Commission to buy AMI Insurance's "good assets" for $380 million earlier this month.
The terms of the bailout will see AMI's earthquake liabilities transferred to a Crown-owned company, leaving IAG free to pick up the good assets.
Mr Brownlee said the sponsorship deal with the insurer was a major victory for Christchurch.
He thanked the 400 workers who made it a "personal mission" to build the new temporary Addington stadium in less than 100 days.
"AMI's sponsorship and continued backing of sport and entertainment in Christchurch is welcome, especially as the future of the quake damaged AMI Stadium remains in question.
"It will deliver some normality for Cantabrians who have not been able to enjoy large sporting and entertainment fixtures for more than a year."
The new stadium opens this Saturday with a Super 14 match between the Crusaders and the Cheetahs.