Hamilton has racked up $255.89 million in new debt in the past five years - with Claudelands Event Centre tagged as the single largest contributor.
New figures show the event centre and city roading contributed to half the council's new debt since 2007.
The city council proposes to cut services and sell assets to pay it off.
Next month the city's total debt is expected to reach $400 million - and more than half of this was due to recent spending.
In response to the figures, the council's finance and monitoring committee chairman Dave Macpherson said hindsight showed the council made some wrong decisions.
"In 20/20 hindsight I don't think we would have done it and I don't think the community would have supported it either. In hindsight it [$255.89 million in new loans] is too much."
But he said that while people were now saying the council should not have spent money on Claudelands and the V8 Supercar series, at the time there was no recession and there was widespread consultation and community support for the spending.
The figures, requested by a city councillor during last week's draft long term plan hearings after the council was criticised for excessive spending, put the latest cost of the loan-funded Claudelands Event Centre at $69.458 million and city roading borrowing at $68.026 million.
The council also took a loan of $19.3 million to host the V8s for five years and borrowed $11.9 million to revitalise the city centre.
Of the $236.5 million spent on infrastructure, just over half (56.6 per cent) was spent on the city's core business and 40.6 per cent was spent on "nice to have" items.
But Hamilton Deputy Mayor Gordon Chesterman said the figures proved to its critics that the council was sticking to its core business - pipes, water and roading.
"It shows people are mistaken when they say councillors have wasted money over the last five years ... the figures show a balanced view of the debt."
He said that in four years, people would agree the events centre was a good investment.