Mr Hawkins announced his campaign today, describing his return to the local political arena as unexpected.
Significant changes in the political landscape since last year's council elections, as well as the by-election's timing, were behind his decision to stand, he said.
Mr Hawkins said nobody before the last election had anticipated the scale and speed of the government’s reform programme.
Rates capping and regional government reorganisation required robust responses, he said.
"I am standing to offer leadership that is ready to go on day one, that is willing and able to challenge the government’s reforms, and that is prepared to make decisions in the best long-term interests of the city," he said.
Mr Hawkins joins former city councillors Bill Acklin and Conrad Stedman in the race, alongside heritage advocate Jo Galer.
Other candidates are Lync Aronson, Richard Knights and Pamela Taylor.
A by-election is required after the death last month of city councillor and former mayor Jules Radich.
Nominations are open until March 2 and the by-election date is May 12.
Mr Hawkins was previously elected on a Green Party ticket, but said he was running as an independent candidate this time.
"My values haven’t changed," he said.
"I will continue to prioritise building stronger communities, looking after our natural environment and strengthening ties with mana whenua and Māori more generally."
Mr Hawkins said his thoughts were with Mr Radich's wife Pam Walker and their friends and whānau, and he expected the by-election process would be tough for them.
Voting opens on April 10.
Mr Hawkins was a councillor from 2013 to 2019 and then mayor from 2019 until 2022. He lost the mayoralty to Mr Radich.
