Wet'n'Wild Sydney, which is set to open in December, has promised to bring a "world-class water park" to Sydney, attracting a million visitors annually.

The park will offer 42 attractions including the nation's largest wave pool and several "world-first" rides.

But Kiama mayor Brian Petschler believes Jamberoo Action Park will stack up well against the new addition.

"I'm confident Jamberoo Action Park can hold its own," he said.

"The owners have put an extraordinary amount of money into new features. There might be a change in some numbers, but I'm sure the park is working on a program to help people come down here."

Kiama Tourism manager Susie Scobie agreed, denying any suggestion that the park's patronage was under threat.

"I can't see the numbers dropping off dramatically," she said.

"It's like a new cafe - people will always try it out but they end up going back to what they like.

"I don't think tourism in the area will suffer at all.

"Yes, the park is one of the four major attractions, but people don't just come for one thing - they like to visit Kiama and Jamberoo for a range of reasons."

Jamberoo Action Park started its $40-million Kangaroo Island master-plan development last year, building the Funnel Web water attraction and Banjo's Billabong, the largest aqua-play structure in the southern hemisphere.

A new 1700-space car park was also built.

Last season was the park's busiest, with visit numbers up 42.5 per cent.

Cr Petschler yesterday refuted claims any loss of business at the park could flow into Jamberoo, hurting tourist spending at nearby eateries, accommodation providers and other visitor spots.

"I think most of the village of Jamberoo operates separate to the action park," Cr Petschler said.

"There is only a small amount of accommodation in the town and the cafes, clubs and pub operate basically at a local level, so I don't believe there'll be any negative flow-on effect."

Jamberoo Action Park executive director Dax Eddy said the owners welcomed any new attraction that helped keep tourist dollars in NSW.

"Any new entrants into this market will help build on existing tourism offerings available in NSW that will greatly assist in stemming the tide of holiday-makers travelling to the Queensland theme parks," he said.

"Jamberoo Action Park will continue to focus on operating and providing a world-class entertainment experience, as it has done for the last 35 years, following a defined and developed business strategy."

The park is still gearing up for a bumper season.

It is set to introduce a new season pass along with new school packages offering lunch and refreshments.

The Wet'n'Wild Sydney park, is being developed by Village Roadshow Limited.