Hong Kong Free Press (HKFP) reported the man was rescued off Tung Wan Beach after police received a report of a man falling unconscious.
Responders performed CPR before he was taken to Peng Chau Clinic.
Police told HKFP the Kiwi was later airlifted to Pamela Youde Nethersole Eastern Hospital and pronounced dead.
The swimming event includes 5.5km, 3.4km and 1.7km swims around the island.
More to come.
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