"I was told to shut up, leave the room, not to say anything, and you do because they've got the guns, there's no choice."
Mr Berg said he originally thought the bust was a robbery, and it wasn't until the group led him to the elevator that he asked who the men were.
"That's when I actually confirmed. I asked them 'who are you guys?', and that's when they confirmed they were the police," he said.
"I thought we were going down to get shot for sure."
Mr Berg was led to a city backstreet, where the cops claimed he had tried to sell drugs to a fellow officer. They forced him into a white taxi and shows him two piles of drugs - 160 ecstasy tablets - that they claimed to have recovered from him.
Mr Berg said he was thinking: "This is a complete set-up".
Thrown in a small communal prison cell with about 70 others, Mr Berg said he grew concerned over the weeks he was imprison awaiting trial as he heard news of people being murdered during the vicious crackdown.
"Obviously I was quite concerned ... it's the worst time to be accused of such charges," he said.
"I thought regardless of my innocence, I didn't think that I'd be freed."
Mr Berg believed he had been framed, and had just about lost hope, believing any evidence of his innocence would have been destroyed.
But CCTV footage of the arrest, obtained by subpoena from the hotel, showed that Mr Berg had been taken by police from his hotel room rather than arrested on the street selling drugs as they had alleged.
The evidence led to Mr Berg's acquittal in September and he has returned to Australia with his partner Marvie, where they are looking forward to starting a family in freedom.
Mr Berg says he feels lucky to have escaped prosecution for the false charges, but there are many others who haven't been so fortunate.
He says many innocent people are being framed and killed in the Philippines thanks to the president's extreme order.
"This sort of thing seems to be happening all the time now, it's not the matter of finding a crime now it's what they can prove, and they've shown that they can prove a lot just by lying," he said.
Since Mr Duterte, nicknamed "The Punisher", came to power on June 30, the death toll of his murderous drugs crackdown has exceeded 3600.
He was elected in May on the promise of preventing the Philippines from becoming a "narco-state" and vowed to kill those involved in importing or selling illegal drugs.
In his victory speech, he called on the public to shoot anyone they suspected of taking or dealing drugs.