Ms Bui said the city's retailers would be making the most of the busy shopping day.
"They have to be in it to win it," she said.
"It is one of those things that retailers should take advantage of and it is a much needed boost for retailers in the central city."
Ms Bui said Boxing Day was fast becoming a day when residents would buy friends and family Christmas presents.
"Some people put off buying their presents until Boxing Day, when they know they can get a bargain."
She said the large crowds rarely put people off venturing into the central city.
Mike Lee from Rotorua store Serious Fun said Boxing Day was typically the store's second busiest day of the year, coming second to Christmas Eve.
Mr Lee said the store, like several others in the central city, had rostered on more staff and security to ensure the day ran smoothly.
He said rather than having huge sales like other stores, Boxing Day was when Serious Fun released new stock.
"It's a great drawcard to get people to come into the store."
Mr Lee said Rotorua being a popular tourist destination meant the city was usually full of not only residents but domestic and international tourists as well.
"The Boxing Day boost that most retailers get is a great start to summer."
He said he hoped it would be a sign that the rest of summer would be busy.
"Typically, whether we have a busy summer is dependent on the weather. We have had a hot winter so we are hoping for a wet summer, so people won't be so inclined to leave town."
Rotorua publican Reg Hennessy, who is vice president of Hospitality Association of New Zealand, said several of the city's bars and restaurants were also gearing up for a busy Boxing Day.
"It is usually one of the busier days of the year."
He said he hoped Boxing Day would be the start to a busy summer of trading.
"I know a lot of others are hoping it will be the start of a busy season."
Meanwhile, operator of the Cedarwood Lakeside Resort and chairwoman of the Rotorua Association of Moteliers, Fiona Suurenbroek said bookings for Boxing Day were down on previous years.
"So there is plenty of accommodation still available," she said.
"We expect that we will have last-minute bookings."
She said Rotorua moteliers were hoping for and looking forward to a good summer, which she said would "alleviate some of the pain moteliers experienced throughout the Rugby World Cup period".
However, she said indicators were not looking good at this stage.
"Boxing Day through to early January looks steady for a number of our members yet still not at the levels we have experienced previously at this time of the year."