A prominent vegan activist has been filmed furiously venting at a driver he believes drove too close to him during a weekend ride in Adelaide.

Harley Johnstone made an expletive-laden tirade at the driver, who had pulled over to the side of the road after the near-miss with the cyclist on Norton Summit on Sunday.

"You want to kill me? I'm here. Kill me," Johnstone shouted after trying to open the door of the Alpina.

"My f—ing mate got killed in Sydney by a f---ing car driver like you.

"One day someone's going to f---ing kill me.

"If you're going to f---ing kill me, I'm right here."

The driver, who doesn't raise his voice during the exchange, repeatedly asks Johnstone to settle down.

"Settle down, because one day someone is going to f---ing clock you," he said.

As Johnstone catches his breath and shifts around as he stands to deal with the adrenalin-rush, the driver drives off.

"It was within touching distance and coming around a blind corner with double yellow lines on a busy Sunday morning," fellow rider Gruffudd Pugh-Jones said in a subsequent video posted on YouTube.

"Shook me up a bit."

"Harley understandably reacted somewhat angry because he's obviously been in a lot of situations before where cars have put him in a lot of danger."

But not all YouTube commenters were as sympathetic.

"There was nothing wrong with that over taking manoeuvre the cyclists attitude and body language was disgusting he should not be allowed to use the roads if he is going to act like that ," a user named MADCOW Moo wrote.

"Man that didn't look that close, looks fairly tame compared to my London commute," wrote Kevin Cuthbert.

Leanne Ratcliffe, also known as 'Freelee the Banana Girl.' (YouTube) (YouTube)

Johnstone was well-known for his long relationship with Leanne Ratcliffe, the vegan lifestyle blogger better known as Freelee the Banana Girl .

Johnstone alleged Ratcliffe was physically abusive towards him during their relationship with a video posted in September last year.

"The truth is she was so abusive to me, she used to hit me a lot. And I was cool with it, then last year, I'd hit her back. I think if you hit like a man you're going to get hit back," he said.

"I never ever hit Freelee in the face, I never used more force than was needed I would just push her off, pin her down and punch her in the leg real hard and say, 'f--- that's not acceptable behaviour, control your anger'."