His father Aaron Duffy said their dog, Teddy - a cockapoo raised the alarm.

The 42-year-old told the Press Association: "My wife was upstairs hHoovering at the time and the dog ran upstairs and basically went berserk so she knew something was not right.

"When she went downstairs she saw our older son watching TV and asked 'where's Riley?'

"The dog was barking like mad and running backwards and forwards to the tumble dryer but because it was so dark inside, she could not see where Riley was.

"They could hear banging and crashing and could see his iPad going round and round. We suspect he was inside for a couple of minutes.

"She pulled Riley out and started pouring cold water over him.

"I arrived home about 40 seconds later, stripped him and took him into the shower to cover him in cold water. After that I just dialled 999.

"It doesn't bear thinking about what might have happened if the dog had not been there."

The accident happened at the family home in Bangor, Co Down, Northern Ireland, on Sunday.

Riley was rushed to the Ulster Hospital, Dundonald, and is currently receiving treatment.

He is expected to have a CT scan to check swelling to his head, Mr Duffy said.

"He's doing very well, apart from the burns and bruising to the head," he added. "But he is in good enough form and is getting back to his old self."

A hospital spokeswoman has described the boy's condition as "comfortable".

Mr Duffy has spoken out to warn other parents of the dangers posed by tumble dryers and to thank ambulance and medical staff for their swift response.

He added: "You read about these things happening but this happened in our house and I just want other parents to be aware.

"We have a bigger than usual tumble dryer because there are six of us in the house and we have lots of laundry.

"It's not an old model or anything but by just turning the dial and closing the door that triggers it to start.

"It angers me really, when I think about could have happened.

"Kids have suffocated and the heat drawing the air could have killed Riley quicker.

"Only for our dog reacting the way she did, my wife would not have known something was up."

It is the second time Teddy has warned of danger in the last two months.

"The dog alerted us that an iPhone charger was catching fire," said Mr Duffy.

"She's a brilliant dog, it is amazing."

Meanwhile, in a Facebook post, the Northern Ireland Ambulance Service described the incident as "horrific" and said crews were on the scene within six minutes.

"Today, Reilly is back to his old self and we will maybe get him a wee visit to the station next week," NIAS said.