Claudelands Event Centre management is being warned not to pad booking forecasts to make the $68.4 million centre look good.
Hamilton City Council finance and audit chairman Dave Macpherson yesterday queried why the council's projections for the next few months were just the right number needed to meet its target.
He also raised concerns about the numbers being overly ambitious and unrealistic.
But Hamilton City Council event facilities operations director Chad Hooker told yesterday's operations and activity performance committee the numbers were achievable and had been based on upcoming events.
He was confident the event centre would secure another 30 functions and meetings, and eight more conferences - not already pencilled in - between April and June.
This would bring the council in line with its revised target of holding 211 events - down from 315 - in the first year.
"My worry is we have got a picture that matches the plan ... in this situation once bitten twice shy," Mr Macpherson said.
Earlier this year, the council received a damning review of the original Claudelands business case which found the projected revenue had been overstated and costs understated.
Mr Macpherson said the council would find itself in a position of not trusting any figures presented to it if the latest one proved to be wrong.
Councillor Angela O'Leary also questioned why some bookings were included in the update as being secure, when there was only a 70 per cent chance of some of them being contracted.
"To me, a confirmed booking is signed on the dotted line."
Hamilton City Council events and economic development general manager Sean Murray said the support of Hamilton and greater Waikato was needed to prove the centre could attract large numbers.
"At the end of the day, the real opportunity for exposure for the venue will be delivering successful events. If we are talking about a big event for the arena we need to demonstrate we can get the numbers into the room."
Mr Murray said the event market was tough and staff were working hard to attract new events and retain existing ones. The conference centre was attracting the most revenue, while getting events into the arena was more difficult.
For the coming year, Claudelands has attracted a number of new exhibitions, including Bumps, Bubs and Beyond and Armageddon to the event centre.
The council was also told its decision last year to not pay $450,000 towards air conditioning in the exhibition halls - a missing element in the centre - was having a negative effect on business.
Meanwhile, Mystery Creek Events Centre announced this week it was planning a large redevelopment of its 88ha facility, which hosts the Parachute Music Festival and National Fieldays, which could result in even more competition for the new venue.