(CNN) The father of a 21-year-old British woman who disappeared after a beach party on a Cambodian island fears she has been kidnapped.

Amelia Bambridge was last seen on Police Beach on Koh Rong island in the early hours of Thursday. An extensive search has been launched, with her family arriving in Cambodia to help with the investigation.

"I don't think she's had an accident," father Phil Bambridge told the UK's Sky News . "If she'd had an accident, she would have been found by now."

More than 100 police officers and volunteers have been deployed to assist with the search, Lt. Gen. Salideth Peuo of the Cambodian National Police told CNN.

Bambridge, from Worthing, West Sussex, had gone to the party on Wednesday, according to the Lucie Blackman Trust, a charity that highlights the plight of missing or jailed British travelers abroad. She was staying at a nearby hostel.

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