Hamilton City Councillors are questioning why they had no notice that V8 Supercars Australia wanted to remove the event from the city, and are criticising a "rushed" decision-making process.
Next year will be the final year Hamilton will host the V8 supercar event, after councillors voted 6-4 on Friday to accept the company leaving a seven year contract two years early.
Hamilton council has invested more than $40 million into the event since the contract was signed in 2006.
Council chief executive Barry Harris has reportedly confirmed the deal was negotiated over the last few months, but councillors are claiming they had no idea about negotiations.
Councillor Angela O'Leary said she was told about the issue on the same day councillors were expected to make a decision based on limited information.