Mr Hac, 27, told the Herald he was walking home with friends when, about 100 metres from his apartment, he saw eight police officers and a sniffer dog rush past him carrying a camera.
He said he was threatened with arrest when he asked what they were doing. Believing he was within his rights to photograph incidents occurring on a public street, he took out his BlackBerry and started filming.
"One of the officers noticed I'd filmed them and aggressively came towards me … they said, 'Give me your device' and I said I'm terribly sorry - I would have apologised 100 times - and they said 'You're not allowed to film us' because there were other officers from different areas of the police," Mr Hac said.
An officer snatched Mr Hac's mobile from his hand, despite him repeatedly saying he did not consent to them searching it.
He said the officers did not know how to delete video from the device so one of his friends, who was watching from a few metres away, had to assist them.
"They looked into my inbox, which is where my SMS and email were … they looked through my photos," he said.
Mr Murphy said a decade ago police could not even demand identification, but recent laws such as the Australian Anti-Terrorism Act 2005 gave them "extraordinary powers".
Mr Hac said he went to the police station to file a complaint yesterday afternoon and was assured the police involved would be spoken to and all Kings Cross officers would be told that citizens had the right to film them doing their job.