Police were called to a Canterbury Hospital at 8.45am after a man showed up to the ER with stab wounds to the head.

Officers were told that just 45 minutes before, the 34-year-old had been assaulted by three men, with at least one known to him.

The alleged attack happened inside a unit on Beamish Street in Campise.

A later search of the unit uncovered three machetes, police say.

The man and a woman known to him rode to the hospital for treatment on a motorcycle.

Police seized the bike for forensic testing.

Investigators believe it was a targeted attack.

Following investigations, three men aged, 43, 44 and 45, were arrested from Beamish Street.

All three were charged with wounding a person with the intent to cause grievous bodily harm.

The 44-year-old man was also charged with possessing a prohibited drug.

All three men were refused bail to appear before Parramatta Local Court today.