Bali’s deputy police chief says some officers have made admissions about the alleged extortion of a group of Australian men whose bucks’ party was raided on the resort island.

Bali police are conducting an internal affairs investigation into claims officers threatened the Australians with indecency charges if they didn’t cough up about $25,000 in bribes after a stripper was found at their party.

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Reports in June said the 16 men were on the last night of a five-night bucks celebration in Seminyak when security broke up the party in a private room of an upscale restaurant.

The Melbourne men claimed a violent fight broke out in which they were pistol-whipped and tasered.

Indonesian authorities in Australia apparently asked Bali Provincial Police internal affairs to investigate claims that two of the men were escorted to ATMs to withdraw $25,000 in cash, or else face 10 years’ jail for indecency.

On Tuesday Bali Provincial Deputy Police Chief, General Nyoman Suryasta, told reporters seven officers had been implicated in the alleged extortion, though the extent of their involvement had yet to be determined as investigations continued.

“We will take strict measures. This has already tainted the organisation’s name, especially the Bali Provincial Police,” General Nyoman said.

When asked if the extortion had happened General Nyoman replied: “Correct”.

He confirmed that admissions had been made but the sum of $25,000 had not been admitted.

“Only lots of [money] bills. What’s clear, they have violated the ethical code. It’s unjustified,” he said.

General Nyoman said an internal affairs trial date would be set.

The heaviest penalty for violation of the professional ethics code was expulsion from the force and the lightest penalty was an apology, he said.

Kuta’s police chief, Ida Bagus Dedy Januarta, on Monday denied the Australian claims and showed reporters a letter he said was signed by all the men saying they didn’t have to pay for their release from police custody.

General Nyoman said on Tuesday that Ida was only a witness in the investigation.