Perth man's urgent warning after he was stabbed during a Facebook marketplace sale

A man who was stabbed while trying to sell $2,000 worth of jewellery through Facebook Marketplace has opened up about the terrifying ordeal.

Will, 20, agreed to meet his alleged attacker outside of a café in the inner-city suburb of Highgate in Perth last week.

'It was like something you would see in the movies I could not believe it happened,' he told 9news.

The incident took place at 10am on Thursday, when the buyer allegedly 'snatched' the items off Will and ran down Harley Street.

CCTV cameras in the area captured Will chasing the man down the suburban street after he took the items and ran.

A person nearby heard Will shouting and tried to stop the suspected thief by pushing a bin over in front of him, and that's when 'things turned violent'.

'I had been robbed and I was trying to get this guy to stop,' Will said.

He heard a person yelling 'he has a knife,' Will looked down and saw blood pouring out of his abdomen and thigh.

'I have never seen anything like it,' he said.

Bystanders saw the attacker throw the knife cover and head towards Chatswood Road and Beaufort Street.

Will was taken to hospital for emergency surgery 'to check that his organs had not been punctured.'

'It was very excruciating for the few days following and I am still in a bit of pain,' Will said.

'I know lots of people who use the platform, but just be careful.'

Police are hoping CCTV images of the man will help someone identify the attacker.

WA Police detective acting sergeant Millie Phelan asked anyone with information that could help identify the attacker to contact the police.