Instead, he would pick apart Goff's campaign and also endorse himself as he sets his eyes on the 2019 mayoral campaign.
"I am not stepping out of the race. I remain a candidate and will continue to encourage people to vote for me, but I will now focus more on the lack of change a Phil Goff mayoralty will bring," he said.
He told the Herald he has been "strongly encouraged to pull out" of the race.
"The reason people have approached me is because they, like me, share the idea that Phil hasn't got the answers to fix Auckland's problems," he said.
"So I think the most responsible thing for me to do is rather than pull out is frankly to double my efforts to make people aware that a Phil Goff mayoralty seems inevitable and that's not going to fix the problem, that's not going to fix traffic congestion or more affordable housing."
Commenting on who had asked him to withdraw, Thomas said he'd had approaches by four or five different parties.
"Some of those approaches are clearly from people who are supporting other candidates, but I can tell you two of them were from people who are not aligned with any other campaign - they just simply agree with me that a Phil Goff mayoralty will continue effectively what Len has done and not make enough progress on the key issues and spend too much money doing it."
Watch: Explaining the local body elections
Thomas said he was not keeping his hat in because of his ego.
"My motivation when I started this was not just to be the Mayor of Auckland. I want Auckland Council better led, I believe in this enterprise ... I thought the best opportunity for me to fix the problems was to stand as mayor but what I'm now turning my mind to is the 2019 race for which I will be a candidate."
He said he was aware of two polls that showed Goff had "a considerable lead".
"People have asked me to consider my position because they think, as I do, that a Phil Goff mayoralty would not deliver the new leadership that Auckland needs," he said.
"I believed the best way for me to improve Auckland Council was as mayor, but if current polling is confirmed and Phil Goff wins, I will find a way from outside council to make council more relevant for people - as part of preparing a campaign for the Mayoralty in 2019.
"I will use the remaining weeks to make people aware of the lack of change a Phil Goff mayoralty will bring and to encourage people to vote positively for a new mayor who can fix the dysfunction that exists between Auckland and its council."
Thomas told the Herald that Aucklanders were concerned about housing and transport, but people had opted for who is best known.
"I've been part of council for six years and we've just burnt people off. We're the ones who disillusion them. We consult, we spend a fortune in consulting and then we don't do what they tell us that they want done.
"Unsurprisingly, people don't have a choice. If Auckland Council with a 15 per cent satisfaction was a business in the real world it would have collapsed.
"People can't avoid using council, they're forced to use our services, but what they do is turn off in other ways and they've turned off on the mayoralty because of us ... so this hasn't been a contest about ideas, it's been a contest about profile."
