Waikato police have arrested a man following a serious assault at a Ngaruawahia address.

Police were called to a Thomas Street property around just after seven last night.

They arrived to find a 50 year old man unconscious but breathing.

Police arrested a man at the scene, and charged him with serious assault.

The victim is in Waikato hospital, but is yet to be spoken to by police.

A scene examination took place this morning.