A constable who was allegedly stabbed in the head while on a routine traffic patrol in Sydney’s CBD is recovering from skull fractures in hospital.

The man accused of stabbing 35-year-old Constable Elvis Poa has been charged with causing grievous bodily harm with intent to murder.

NSW Police say Poa and a partner were on traffic duties just after 1pm on Sunday on the corner of Castlereagh Street and Park Street in the Sydney CBD when they were approached by the 34-year-old alleged attacker.

The man allegedly produced a 30-centimetre “kitchen-style” knife and stabbed Poa in the back of his head two to three times.

He then fled, pursued by Poa and a female constable, along Park Street and into Hyde Park.

The two constables confronted the man there, ordering him to drop the knife. As other officers arrived as back-up, the man was tasered and taken into custody.

“Whilst he was in the park, he still had the knife in his hand and he was demanding that police shoot him,” Detective Superintendent Martin Fileman said on Sunday.

The man was known to police but had no history of mental illness recorded on the police database nor any “substantial” criminal record, Fileman said.

“This was very much an isolated incident and there is no further threat to the public,” he said.

Poa was treated by paramedics for two wounds to his head.

He was taken to St Vincent’s Hospital where scans revealed he suffered two skull fractures. NSW Police released an image of Poa on Monday, and said he was in a stable condition.

Premier Chris Minns said the incident highlighted the difficulty and danger of policing as a job. He said he hoped to speak to Poa later on Monday.

“The officer involved showed enormous courage,” he said.

“To not only be the victim of an alleged assault, but also to apprehend the person who is alleged to have committed the offence.”

The 34-year-old man was arrested and taken to Royal Prince Alfred Hospital under police guard, for assessment.

He has since been released from hospital and charged with cause wounding/grievous bodily harm to person with intent to murder.

He was refused bail to appear before Downing Centre Local Court on Monday.

The incident follows a series of high-profile knife crime incidents including an attack at Sydney’s Bondi Junction shopping centre where six people were fatally stabbed, and another attack on a bishop who was stabbed while delivering a sermon at a Western Sydney church.

The NSW government has since brought forward laws that will allow police to stop and search people for a weapon without reasonable suspicion or a warrant in designated precincts.

-with AAP