The director of a livestock saleyard in Victoria's west has confirmed his business partner is one of three Australian men arrested in Serbia in connection with an alleged cocaine shipment.

Victorian businessman Rohan Arnold. ( Supplied )

Businessman Rohan Arnold, 43, was arrested with two others at a Belgrade hotel after police stormed the lobby with their weapons drawn yesterday.

Brendan Abbey and Mr Arnold were due to open the $16 million Western Victorian Livestock Exchange together in Mortlake on Monday.

"We're just in amazement — I'm dealing with it right now it's come as a complete shock to us," said Mr Abbey.

"[It] came completely out of the blue."

The saleyards are tipped to be the most modern in Australia, with stock agents as far as the Northern Territory expected to bring cattle to the facility's first sale in three days.

Serbian police footage showed the men lying on the ground with their hands cuffed behind their backs. ( Supplied: Serbian Interior Ministry )

"We've just had an emergency meeting, and we've had a phone hook up and its all systems, it's still going ahead," Mr Abbey said.

"You couldn't time it worse, it's absolutely the worst time. We're under the pump here, everyone's working 12-15 hour days to get it finished in time."

Serbian media outlets have posted images of Mr Arnold, calling him the "Australian king of steel".

Belgrade police said the arrests were in connection with a 1,280kg cocaine shipment seized in Sydney last year, which had a street value of half a billion dollars.

Properties at Goulburn and Murrumbateman just outside Canberra were also searched in connection with the arrests.

Local police released a video of the men's dramatic arrest in Belgrade — which shows armed police pinning the men down and handcuffing them face-down.

A bag filled with foreign currency banknotes from Europe, Australia, China, Thailand, Singapore and Vietnam also was shown, and police said the arrests were made during a "money handover".

A gun was also found.

Police said the cocaine — which had a purity of around 78 per cent — was found concealed in a container of pre-fabricated steel that arrived in Sydney last year.

Police escort one of the men into a government building in Serbia following a raid on a Belgrade hotel. ( Supplied: Serbian Interior Ministry )

Mr Abbey said he last spoke to his business partner on Sunday.

"No, I never suspected anything. I was just talking to one of our shareholders, we just can't — it's unbelievable," he said.

Mr Arnold told him he was going away for the week, and would be back before the saleyard opening.

He said Mr Arnold's wife sent a text message to his wife this morning at 6:00am.

Mr Abbey said there was no connection between the alleged shipment and the saleyards.

He said he was not worried about there being any financial repercussions for the livestock exchange.

"He's one of nine shareholders it's not going to affect anything here, everyone is still supporting it — we'll still have our first sale on Monday."

Mr Arnold's career in the steel manufacturing industry has spanned more than 20 years.

Canberra lawyer Ben Aulich confirmed he would represent Mr Arnold, but said he had not yet spoken to his client.

He said he was considering whether to travel to Serbia and is seeking help from the Department of Foreign Affairs and Trade.