The complex was leased to Russian billionaire Mikhail Khimich whose business ran the pools but shut them earlier this year for renovation. Khimich's company bought the lease interest in 2010. No workers have been on the site for weeks.
Locals have called the resort "a bloody mess" due to the partially completed state and say the ongoing closure is not helping businesses in the small waterfront town north of Auckland.
Belgravia says it works with more than 40 council and state government authorities and manages about 100 aquatic, sport, health and wellness complexes here and in Australia, with more than A$2b of assets under management and A$120m annual turnover.
Belgravia lists 10 New Zealand operations where it has interests, mostly in the upper North Island.
They are Ngaruawhai Swimming Pool, Northcote College Pool in Auckland, Huntly Aquatic Centre, Tuakau Swimming Pool, Trust House Recreation Centre in Masterton, Franklin Pool & Leisure in Pukekohe, Pukekohe's Jubilee Pool, Mt Albert Pool in Auckland, Whiteside Pool in Waiuku and Hamilton Boys High School Pool.
In Australia, the business has interests in 102 properties: aquatic centres, health clubs, sports stadiums, spa and wellness centre, event venues, golf courses and tennis courts.
Last month, Belgravia won two industry awards at the New Zealand Recreation Association's conference awards. Mark Blake, Belgravia Leisure's New Zealand general manager, accepted the awards for excellence in facility management and Huntly Aquatic Centre won an outstanding pool award.
Its biggest play so far here is in Rotorua: "Wai Ariki Hot Springs and Spa is a luxury spa and wellness centre set to open on Rotorua's lakefront in late 2019," that business says.
Te Arawa and Māori culture will be offered "to create a rejuvenating experience to remember and share."
"With Māori culture at its heart, the development draws on the 650 year legacy of the local Maori tribe, Ngāti Whakaue's and Rotorua's famed spa heritage," Wai Ariki says of plans for that complex.