His daughter Saivarun Swatpoklang said her father died at Phramongkutklao hospital following a long battle with cancer.
Mrs Saivarun said Apidet, whose real name was Narong Songmanee, was diagnosed with lung cancer last year and had since been hospitalised.
Nightly prayers are being held at Wat Bang Phli Yai in Samut Prakan until Tuesday and the royally sponsored cremation rites are scheduled on Wednesday.
Apidet was born in Tambon Bang Nokkwaek in Samut Songkhram. He specialised in kicking and was dubbed the 'Kicker of Bang Nokkawek'.
The video above shows Apidet (in white shorts) fighting Payap Sakhunsuk for the 147lbs title in 1967.
Apidet was so dominant in the country's traditional martial art that it was difficult for him to find an opponent.
He then switched to international boxing and became welterweight champion of both Lumpinee and Rajadamnoen stadiums.
He was a trainer at Fairtext boxing camp before his death.
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