Police Commissioner General Riah Phiyega on Saturday expressed concern and shock at the attacks on police officers.

"Violent crime, in all its manifestations, is unacceptable and the South African Police Service will continue to work within the framework of the law to bring these perpetrators to book," Phiyega said in a statement.

This came after two separate attacks on police officers in Gauteng this week.

A Gauteng police reservist died in hospital in the early hours of Friday after he was stabbed in Orlando, Soweto.

Warrant Officer Moladluzi Ramatsetse was attacked on Thursday when patrolling police approached a man thought to have dagga in his possession.

When he tried to search the man he pulled out a knife and stabbed Ramatsetse twice in the chest.

"Ramatsetse managed to draw a firearm as he fell to the ground and shot at the suspect who was fatally wounded. The reservist was rushed to a nearby hospital but unfortunately died from his injuries," Phiyega said.

"My condolences and prayers go out to the family, friends and colleagues of the late Ramatsetse."

In Akasia, Pretoria, while police were trying to arrest a man who allegedly stabbed and wounded another man on Tuesday, he pulled out a knife and stabbed a police officer twice.

The stabbed officer retaliated by firing shots, which killed the man.

Phiyega said the officer was in critical condition at a local hospital.