Waitemata Police is asking for the public's assistance to find 33-year-old Michael Melville

Melville is wanted in relation to a serious assault in Birkenhead on Auckland's North Shore.

A female victim is in hospital recovering from a skull fracture, brain bleed, fractured eye socket and broken nose after being assaulted early on Monday morning.

Melville is known to hire rental vehicles, and may be travelling between Auckland and Dunedin.

He's described as a medium build, 185 centimetres tall.

He has numerous tattoos - including the letters NS on his neck, and a large skull on his forearm.