THREE Australians detained in Belgrade over alleged links to a $500 million cocaine bust could be held in grim Serbian prisons for up to six weeks before they are extradited to Australia.

Construction magnate from NSW Rohan Arnold, 43, former Canberra nightclub security manager Tristan Waters, 34, and a third man, David Campbell, 49, were all detained at gunpoint in the luxury Metropol Palace Hotel in the capital on Tuesday as part of a co-ordinated Serbian-Australian Federal Police operation.

Waters and Arnold are being held in the Padinjak Prison in Paldinjak, 30km from central Belgrade, while Campbell is being held at the Central Prison in Belgrade.

All could be behind bars in Belgrade for up to six weeks as the two countries negotiate to extradite them.

None of the men have been charged.

The Serbian Ministry of Justice told the local paper Telegraf the Australian Government had not yet launched a formal extradition request.

Serbian media is abuzz with rumours about the raids, which saw the Special Police Organised Crime Squad storm the lobby of the luxurious hotel with guns drawn and video-cameras rolling.

A small suitcase was filmed at the scene and police later said it contained a huge amount of cash in 10 currencies — 638,020 euro, 11,350 Australian dollars, 4,000 US dollars, 18,300 Czech koruna, 528,000 Vietnam dongs, 9,000 Japanese yen, 2,940 Chinese yuan, 2,500

Thailand baht, 863 Singapore dollars, 112,000 Serbian dinars.

This equates to $996,267 in Australian dollars.

A gun was also found at the scene. Police described the meeting in the lobby as a “money handover.’’

The men, who have been detained but not arrested, were wanted for questioning in connection with an inquiry by the Australian Federal Police which saw 2576 blocks of cocaine weighing 1.28 tonnes seized in a container of prefabricated steel which arrived from China into Sydney in April.

Police believe the drugs came via China from a source country, but it is not clear if Serbia was that country.

The seizure, worth $500 million on the streets, was the second-largest cocaine seizure in Australian history.

A Lebanese man, Diab Geagea, 41, was also detained by police at the lobby meeting, apparently in connection with false documents.

Inquiries are underway into whether the Australian men were travelling under false passports or had false identification papers.

Consular assistance has been offered by the Australian Embassy in Belgrade.

“We are working close(ly) with Australian colleagues in this case and they have praised us for professional co-operation”, a spokesman for Serbian police told the media.

No Serbian nationals were arrested during the raids.

The Australian Federal Police have a small, permanent prescience in Belgrade.

The men may appear in coming days in the Specijalni Sud (Special Court) in Belgrade for preliminary hearings ahead of any extradition application.

Those court hearings are unlikely to be open to the public.

The raid made front-page news across Serbia, not least because of the dramatic way it was carried out in the marble-lined lobby of one of Belgrade’s finest hotels.

The Bulgarian Ambassador was hosting at event at the Metropol at the time of the raids, celebrating Bulgaria taking over the revolving presidency of the European Union.

A number of diplomats were present at the function but mostly did not witness the raids as they were in a separate area of the hotel.

Serbian folk singer Radisa Trajkovic Djani also told local media he witnessed the raid.

In an unconnected coincidence, the singer’s best man at his wedding, Nenad Stankovic, was once arrested in Australia for drug dealing.