A 12-year-old girl clutching a baseball bat confronted a man as he brutally assaulted the girl's mother, telling him to stop.
Stephen James Reid, 43, of Darfield, has admitted charges of assault with intent to injure and unlawful possession of a shotgun in relation to the prolonged attack on the Runanga woman.
Reid was also charged with possessing an eel spear as an offensive weapon, assault with a blunt instrument, possessing cannabis, and possessing a ball-peen hammer as a weapon, but those charges were withdrawn in the Greymouth District Court last week.
Police prosecutor Steven Greer said Reid and the woman had been in a relationship for almost two years.
When he visited her last Christmas Eve they argued, Reid kicking the woman's truck before verbally and physically abusing her. He punched her twice, placed her in a headlock so tight that her breath was cut and punched her again, splitting a lip.