Police Officer Filmed Punching Handcuffed Man In The Face

The arrest of an alleged South Australian vandal has ended in a dramatic scuffle after the handcuffed man was punched in the face for "spitting" on an officer.

The 22-year-old was being arrested after police were called to Morphett Vale, south of Adelaide, following reports of three men marking graffiti on Saturday.

After arriving at the Woodcroft Drive address just before 4pm, police alleged the trio ran off into a nearby house before officers apprehended the man.

"It will be alleged during the arrest he resisted police and assaulted police including spitting on the face and arm of an officer," a SA Police spokesperson said in a statement.

Video of the incident -- filmed by a man who identifies himself as the accused's cousin -- captures the moment an officer loses his cool and punches the Morphett Vale man square in the jaw.

The accused is then pulled to the ground with the assistance of two female officers while his relative can be heard lashing out at police.

"Get the f*** off my cousin now!" the man filming can be heard screaming.

"You just smacked him in the face you dog."

In a message to 10 News First, the man's cousin said the arrest was running smoothly until the altercation.

"Then as you see he gets punched by an officer while cuffed and pulled to the ground with a knee to his head and while my brother and I stood in complete shock and anger that this could happen," he said.

The 22-year-old was charged with mark graffiti, resisting police and assaulting police.

He was bailed and is set to appear in the Christies Beach Magistrate Court on Sunday.

Police say they are legally unable to comment on the actions of the officer.