"We really had no idea. It's always so hard to tell, especially when a event is being held in a city for the first time.
"Of course we always want as many people to come as possible, but it would be unrealistic to expect 18,000 people to show up on the first go."
She hoped next year's event, which Rotorua will host again, would attract an even bigger crowd.
"Hopefully people have enjoyed themselves enough, and the event's gained a good enough reputation for them to want to come again next year."
Mrs Stewart said if Rotorua wanted to keep hosting the event for as long as possible, it was important that "everyone gets behind it" and supports it.
She said she was thrilled to see a large number of people from out of town attend the tournament as well as locals.
"There were people from Wellington, the Manawatu, Hamilton and even down south, who had travelled specially for the event. That was great to see."
Mrs Stewart praised the teams involved in the event for an engaging tournament and said she felt people had enjoyed watching players perform.
"I think everyone really loved being able to watch some of New Zealand's top players up close and personal."
The children's entertainment and the mascot races had also proved a hit, she said.
Over the weekend social media sites were abuzz with reaction to the tournament, which received mostly very positive feedback from Twitter and Facebook users.
One tweet read: "Back in Auckland. Aftersun, then bed. Great day at the #National7s today in Rotovegas," while another said "Goodbye Rotorua it's been fun, good to leave as the rain sets in."
