Transcript
The video, which was released by a Facebook page critical of the government, shows Frank Bainimarama marching over to Pio Tikoduadua.
The prime minister then grabs the National Federation Party member by the lapel of his jacket, giving him a light shove.
Since Mr Tikoduadua claimed in parliament on August 9 that he was assaulted that day, the government has denied any wrongdoing.
The governing Fiji First party called it a "blatant lie" and Mr Bainimarama insisted he only "spoke sternly" with the opposition MP.
But Mr Tikoduadua says the video proves his critics wrong.
"Now that the video has come out, I think it's told exactly the same story that I've told from day one, including my statement to the police so I think in a way it has cleared me."
Since Mr Tikoduadua lodged a police complaint, an investigation has been launched and the parliamentary speaker is reviewing CCTV footage of the incident.
The opposition MP wouldn't be drawn on what action should be taken.
"I hope that the police will do their work, will do their job. The requirement under the law, given the complaint that I had already lodged with him."
Lawyer and government critic Aman Ravindra Singh says that will never happen.
He says the prime minister should be charged with assault and intimidation.
"If the shoe was on the other foot, and the other bloke had done the same to the Prime Minister, pushed him and shoved him and swore at him and threatened him, and all that, this guy would still be in jail right now. He would have been picked up, processed, charged
Police, the parliamentary speaker and the Prime Minister's office haven't responded to requests for comment.
A police spokesperson told the Fiji Times only the police commissioner, Sitiveni Qiliho, could answer questions, and he was overseas.
Their silence has riled some, including Fijian human rights advocate Roshika Deo.
She says in Fiji, there's a culture of leaders having effective criminal immunity.
"Many coup perpetrators have evaded all forms of accountability and justice. And this has trickled down into many other facets. So this includes cases involving criminal intimidation, assault and so forth."
But experts say the release of the video will make it harder for the government to avoid taking action.
For example, it appears to contradict Mr Bainimarama's claim that Mr Tikoduadua broke his own glasses: the footage shows his glasses falling out of his jacket and onto the concrete moments after the prime minister grabbed him.
During the incident, about six security guards looked on but made no attempt to intervene.