Police have released the identity of a man suspected of killing a property developer and critically wounding his son in a brazen daylight stabbing in Sydney's inner west on Wednesday.

Key points: Police say Mr Kondakov has a large build and speaks with a Russian accent

Police say Mr Kondakov has a large build and speaks with a Russian accent He was last seen hitching a ride in Rockdale, about 6km from the crime scene

He was last seen hitching a ride in Rockdale, about 6km from the crime scene The incident unfolded in Sydney's inner west Wednesday afternoon

Russian national Vladimir Kondakov, 49, allegedly stabbed and killed Albert Metledge, 76, at a construction site on Applebee Street, in St Peters, around 1:00pm.

Mr Metledge's son Antony, 33, was taken to Royal Prince Alfred Hospital in a critical condition.

The ABC understands he is in a stable condition after surgery.

It is believed the men are known to each other.

Mr Kondakov fled the scene and was last seen in Rockdale, about six kilometres from the crime scene.

NSW Police have launched a massive manhunt and have mobilised significant resources including police helicopters, dog units and riot squad personnel in a bid to track the suspect.

Police said Mr Kondakov speaks with a Russian accent and was last seen wearing a high-vis yellow shirt, long blue work pants and brown work boots.

Officers said Mr Kondakov "does not have a fixed address".

Antony Metledge needed emergency surgery for his stab wounds. ( Facebook: Supplied )

Around 3:00pm, Albert Metledge's sister was seen running up Applebee St, saying: "Is he dead?"

She was then taken out of sight by police, where she could be heard crying and wailing.

Inspector Chad Deegenaars said the incident had been traumatic and that Mr Kondakov was "capable of a violent" act.

"He is known to us, but nothing overly alarming," the inspector said.

"Don't approach this gentlemen if you see him."

Albert Metledge's sister is seen being comforted by police after he was stabbed in St Peters. ( ABC News )

In a press conference on Thursday, NSW Police Chief Inspector Michael Merrett urged Mr Kondakov to hand himself in.

"The incident yesterday was a targeted attack, we don't have a reason to believe it was anything other than related to his employment or his presence on the site," he said.

"Having said that the nature of the incident was such that we would not encourage anybody at all to make contact with him but to contact us directly ... It was a violent attack, it was unprovoked.

"I would make this plea to Mr Kondakov ... if you are seeing this please make yourself known to a police station and turn yourself in."