A MAN was arrested on suspicion of causing grievous bodily harm after another man was allegedly stabbed in Newport.

The injured man was found lying in an alleyway with apparent stab wounds on a Newport estate early Thursday morning.

One resident, who did not wished to be named, said a neighbour spotted him covered in blood at about 5.40am and alerted the police.

"He saw somebody lying in the alleyway and went out to see if he was alright," she said.

"He had a bad head wound and looked like he had been stabbed in the back.

"Another resident phoned police and in no time an ambulance, police and forensics were up here."

Police confirmed a man was discovered with two puncture wounds to the back and was taken to the city's Royal Gwent Hospital.

They are investigating whether or not he was stabbed.

The injured man left hospital later in the day. The arrested man is currently in police custody.