On her public Facebook page Cr O'Leary said the attack was disappointing.
"It is unprofessional and disappointing that a chairperson feels the need to write a three-page report targeting an elected member. That is poor governance and bad behaviour. The people deserve better than this, Hamilton deserves better. This is public office," Cr O'Leary said.
"I am an experienced woman with 11 years working for our wonderful city. I understand the current financial strategy, I understand good process, and I very much understand the difference between good and bad governance. I understand exactly what the current strategy is attempting to achieve. Because I understand it, I am opposed to it. I have the right to express my view on all issues that will affect my people. I was elected into public office to do just that."
Mayor Andrew King was not happy with Mr Mallet's attack on Ms O'Leary while she was absent.
"I don't think it is appropriate to be drawing out names of elected members, particularly when they are not here to defend themselves. It's bad taste," Mr King said.
Cr Mark Bunting admitted at the meeting that he was slightly confused over the city's finances and later explained this on social media.
"The essential difference is that the previous council's measure included development contributions in the balance as cash in the bank and the other two measures don't. The previous council's measure makes us look in a healthier state than the other two. At the moment, some councillors are choosing to use some measures, some are choosing to use others to back up their point of view," Cr Bunting said.
"Rest assured I understand all three extremely well. Where I get confused is why we don't just choose one. What I also understand is the nasty political point scoring that is being played by all parties here."
The 2016 pre-election report has now been raised twice by both Cr O'Leary at a residents and ratepayers meeting in March and by Cr James Casson at Tuesday's finance meeting.
The 2016 report written by chief executive Richard Briggs in 2016 stated that Hamilton had achieved a budget surplus in 2014.
"We have achieved budget surpluses Confusion over council finances since 2014 to help balance the books and are on track to do so again this year and for each year of the 10-Year Plan. These surpluses are not profits in a commercial sense as they enable us to balance the books and pay for the assets required to meet the city's growth demands and upgrades to the existing city infrastructure while keeping debt under control," the report said. Cr Casson said the confusion came from this pre-election report.
"Running up to the 2016 elections we were told that the council's coffers were in good stead," Cr Casson said. "All of a sudden when we come into council the coffers are not in good stead so why has this been masked so long? Everybody has been fooled by this."
Cr Mallett said the view was perhaps Hamilton was late to the party in identifying growth.
"I'm not sure if I answered your question," Cr Mallett said.
"No not really," Cr Casson replied.
The 10-year plan is now open for public consultation until April, 30, before council debates the final plan in June.
