Hamilton police are still looking for a person who is on the run, after a 23-year-old man was shot dead in a house early on Sunday morning.

Robert Nelson was killed, and two others received serious injuries after multiple shots were fired in a house on Matthews Crescent in Melville.

It's understood Nelson was protecting his girlfriend from the gunfire when he died.

A 17-year-old man is in a critical condition, and a 20-year-old woman is seriously injured but stable.

They are both in Waikato Hospital.

Detective Senior Sergeant Ross Patterson says the shooting was targeted and it's unlikely the public is at any risk.