But ACT Chief Magistrate Lorraine Walker threw out a more serious assault charge against Royce John Kerrison over the December 2012 incident. She handed down her decision in August and the judgment was published online this week.

The ACT Magistrates Court heard Kerrison had organised to collect his belongings on December 1 after splitting with his partner. The arrangement went awry when he indicated he wanted to take the family dog, Tito, which had not been part of the agreed arrangement.

The court heard Kerrison had paid for the pet, was the registered owner, spent a lot of time with Tito and considered the dog his best mate. But his former partner had paid for and taken the animal to puppy training classes.

Kerrison was accused of assaulting his ex-partner, her mother and her stepfather as he retrieved Tito.

He pleaded not guilty to four common assault charges and one count of assault occasioning actual bodily harm.

Ms Walker dismissed a common assault charge after the prosecution conceded it could not prove the allegation.

The court heard the allegation of assault occasioning actual bodily harm stemmed from a tussle, which also involved the man's former partner, when the stepfather blocked Kerrison's way as he tried to enter the home.

But Ms Walker dismissed the charge as witness evidence was unclear. "In the circumstances, I can only be confident [the stepfather] sought to physically prevent the defendant from entering the property and that the defendant physically tried to push past him," Ms Walker said.

Kerrison conceded he pushed his former partner twice, once into a wall, and also knocked her mother into the dining table.

But his defence argued his actions were rendered lawful by the exercise of claim of right.

It said Kerrison had the right to access the property as he was a part owner.

It said he believed Tito was his property and was entitled to retrieve the dog and that he used only minimum force to do so.

But Ms Walker rejected the defence, saying it would be poor public policy to lawfully excuse "carte blanche" the use of violence to recover property. "A claim of right is not technically a 'defence' but an absence of an essential element of an offence," she said.

"In respect to offences against the person such as assault, [criminal responsibility] is not negated by a genuine belief in a legal entitlement to property.

"[It] is only negated where the offence charged involves some element of infringing … or intending or attempting to do so."

The judgment supplied no further details of the case.