Splash Palace aquatic services manager Pete Thompson says space is tight in its increasingly popular swimming pools.

Swimming groups and clubs are being denied more pool time at Invercargill's Splash Palace complex due to its increasing popularity.

A record 401,000 people used the Splash Palace pools in 2016-17, up from 332,000 nine years earlier, figures show.

Splash Palace aquatic services manager Peter Thompson said clubs and groups were continually wanting more space at the swimming pools, "but there simply isn't any more space to provide".

Robyn Edie Swimmers at the Splash Palace swimming complex in Invercargill are fighting for space.

The Invercargill City Council had planned to build an additional pool at splash Palace in 2021, but last month councillors delayed the $6.4m project until 2023-4 to allow for the museum redevelopment to begin sooner.

In April and May six groups were denied bookings at Splash Palace due to space limitations, Thompson said.

These included a club wanting more space for training, another club requesting 50m training during weekdays, a high school aqua class, a competitive swim meet and a dive course booking.

Splash Palace tried to provide for public lane swimming and aqua jogging at all times, but even this was not always possible due to the popularity of the pools, Thompson said.

"We are often unable to provide adequate space for lane swimming and aqua jogging."

Aqua joggers were down to a "small square" three nights a week and on Sunday mornings and the public swimming lanes were regularly full.

Given the increasing admission numbers at Splash Palace, it was logical to suggest the ability to meet all booking demands and public lane space would continue to be challenging until the additional pool was built, Thompson said.

The H20 Dreams swim club requested 50m trainings once a week on Thursday mornings, but was declined due to no space at that time, he said.

H20 Dreams swim club director Jeremy Duncan, who is the Swimming Southland head coach, said an additional pool at Splash Palace would give the ability to host more national swim meets which would result in a spinoff for the Southland economy.

Another club that wanted more space for training, but was unable to have it was Phoenix Synchronised Swimming, Thompson said.

The club's board chairwoman Jo Leiva said they trained at 5.30am because they couldn't get times during the day.

"It would be nice to get more but we need to understand we are not the only ones."

Additional changing rooms are being built at Splash Palace and will be completed in January or February, Thompson said.

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