A Withers man has been fined after his dog bit a father on the buttocks as he tried to protect his three children from the aggressive animal.

Aaron Norman Roe appeared in Bunbury Magistrates Court on Monday when he pleaded guilty to one count each of owning a dog that attacked and permitting a dog to be in a public place without a leash.

The court was told, Roe’s Staffordshire bull terrier ran across an oval towards children playing in a playground at Maidens Park Primary School on September 14.

The dog “barked and snapped” at an eight-year-old girl before her father stepped between the animal and his daughter.

The court was told, Roe yelled from his car “don’t worry, the dog won’t bite you”.

The father then picked up his daughter before the dog bit him on the bottom.

Roe tackled the dog in an effort to get it “under control” but the dog continued to be aggressive, the court was told.

Roe then became aggressive and swung a chain at the father when he tried to kick the dog off him.

The dog eventually ran off and was nearly hit by a car as it fled.

The father suffered two puncture wounds, which were shown in photos presented in court.

A City of Bunbury prosecutor said Roe had been fined three times last year when the dog was impounded after being found wandering the streets.

Roe argued that the situation escalated because the victim started “screaming like a b**** at the top of his lungs”.

Magistrate Brian Mahon responded “perhaps he was worried about his kids”.

Roe said his dog constantly tried to get out and the day of the attack his “mate” had left a door open.

Magistrate Mahon said the situation could have ended “very, very badly” and a running lead for the dog was a “no brainer”.

“Imagine how you would feel if this animal savaged a child,” Magistrate Mahon told Roe.

Roe was fined a global fine of $1000 plus court costs of $581.35.

No applications were made in respect to the dog.