She said Ozyris was inside the house, playing with toys he had been given for Christmas, and said he "must have slipped outside'' when no one was looking.
Ms Beeching said it was about 10.30am when she went outside to look for her son.
"He was just inside and then I turned around and said, `Where's my baby?' I went outside and my neighbour came running over to me and said my son had been attacked,'' she said.
"I knew straight away what had happened. I ran over and heard him screaming.''
The dog's 39-year-old owner ran after the animal and was bitten on the arm as he tried to intervene. He was taken to Whakatane Hospital.
Ozyris was also rushed to Whakatane Hospital, where he received stitches to his face and ear.
Ms Beeching said he also had several scratches across his body.
"It was horrific,'' she said.
Ms Beeching's father, Paul Beeching, who also lives on Tawa St, said he did not see the attack but heard it happening.
"I just heard all of this commotion, there was so much yelling and screaming,'' he said.
"At the time I didn't know the dog had the boy.''
Mr Beeching said the dog was chained up and that Ozyris had got close enough for it to attack him. He said the dog was always chained up and he had raised concerns about its temperament.
Ms Beeching said she was told by police the dog responsible for yesterday's attack _ which had been complained about several times for barking and rushing at neighbours _ was also now likely to be put down.
"So many people on the street have complained about it so many times,'' she said.
"I don't know if it has been destroyed yet, but I hope it happens soon.''
The dog's owner was to be interviewed by police but officers could not be reached for comment.
Whakatane District Council could also not be reached for comment.
