Liz Mitchell, who is on the society's maintenance committee, says the main hall's toilet, bathroom and kitchen hot-water cylinders had burst, damaging the floor.
The society fixed the kitchen cylinder but is left without men's toilets in the main hall.
It aims to raise $100,000 to fix the damage, and do other overdue projects.
"Any donations would be great to help us reform our hall and get it back to where it was 10 years ago," Mitchell says.
She says the hall bathrooms and kitchen need work done to the floors and walls, and the floorboards underneath the hall stage - where they store tables and chairs - also need replacing.
"Being a swampy area back in the rā [day], we're sitting on piles and in one corner our piles are starting to move."
So far the society has raised $16,000 through a fundraising event which saw the community come together, but it needs more. Mitchell says the society also plans to apply for any grants, and is calling on tradespeople to lend a hand if they can.
The society is having a working bee tomorrow from 8am until lunchtime.
"It will be really great to get some help for the community," Mitchell says.
"Tradies can donate time. We're having a working bee for all the Cook Island members, Pacific Islanders or whoever in the Rotorua community."
Food will be provided but contributions are also welcome, and volunteers are invited to bring materials such as cleaning products, lawnmowers and tools.
The society is also working on upgrading policies and procedures to bring everything up to scratch.
Mitchell says that, despite a lot of projects over the years, some maintenance has fallen by the wayside.
The society has been around more than 20 years and has about 185 members.
It runs culture groups, Tivaevae Cook Islands quilting classes, church and has a community garden. She says the society is important, particularly for the young and elderly.
"We're trying to bring out our culture and craft for our young people.
"It's place we can gather to share our stories and history, learn our craft, our reo, to combine all Pacific Island people not just Cook Islanders. The hall is there for their use.
"It's really important for our wellbeing to keep the culture alive."
Any tradespeople willing to share knowledge or help out can contact the society's vice-chairwoman Tere Mitchell-Piua on 021 031 8237.
The working bee is at the hall at 101a Clayton Rd from 8am Saturday.