Former radio shock jock Iain Stables punched his ex-girlfriend's father and brother in the head and spat in her mother's face, a Wellington jury has heard.

Iain Phillip Stables, 40, of Taupo, has pleaded not guilty to assaulting Martin O'Hagan, Robert O'Hagan, threatening to kill Martin O'Hagan and, as a male, assaulted Marianne O'Hagan on March 20, 2011.

He pleaded guilty to one charge of intentionally damaging a car.

Crown prosecutor Ian Murray told a jury in the Wellington District Court that Stables and Kimberley O'Hagan, his girlfriend at the time, had been living in a flat attached to her parent's home.

They evicted him on March 20, and he become enraged.  He came out of the house ripping up the eviction notice and saying it was illegal.

"That enraged him, he was so angry that he deliberately rammed his four wheel drive car a number of times into the back of another car at the property."

Murray said during an altercation, Stables punched Martin O'Hagan in the head, then spat in the face of Marianne O'Hagan.

When she said he was sick and needed treatment before returning to the house Stables followed her and there was a tussle over a door.  Marianne O'Hagan fell, hitting her head on a stair leaving her dazed.

"He continued on undeterred, punching holes in a fence, throwing a pot,'' Murray said.

He then punched the father, Robert O'Hagan, in the side of the face and threatened to kill the brother Martin,  Murray said.

He then got into his car and then rammed the back of a car belonging to the O'Hagan's several times.

Stables was picked up by police shortly after and told them he could not be culpable in his state of mind.

Defence lawyer Gretel Fairbrother told the jury Stables simply denied the assaults happened at all.

The trial is expected to take the rest of the week.

The Dominion Post