Tradie attacked by three dogs in Sydney

Three dogs that mauled a tradesman, leaving him with injuries to his legs, chest and back, have been put down.

The 37-year-old had gone onto the Kenthurst property on Pitt Town Road on Friday morning to do a job when he was set upon by three American Staffordshire terriers.

Police performed first aid until CareFlight paramedics arrived, and the man was then taken by ambulance to Westmead hospital in a stable condition.

Neighbour Robert Brooks told 2GB he was prompted to look over the fence after hearing "horrific screaming and yelling".

"These dogs are just attacking him and he's just helpless, and we're helpless as well," Mr Brooks said.

"The first reaction is to try to jump over and get [the dogs], but mate, there's no way. We're going to sort of get mauled ourselves.

"It was just horrific mate. We couldn't help the poor guy, you know?"

After escaping from the animals, he was assisted over the property's front fence where an off-duty nurse performed first aid before police, paramedics and a CareFlight helicopter arrived.

Mr Brooks claims the tradesman had "big puncture wounds" on his arms, back, thigh and calf.

"There was blood but there wasn't actually blood gushing out, it was actually torn down to his muscles," he said.

The property owner's daughter reportedly also suffered injuries in the attack.

One neighbour said locals were fed up with the dogs roaming around and they had asked the owners to act.

"We've asked them several times over two years. We send them text messages with photos of the dogs in our yard," Michelle Gil said.

"It was just always going to come to this."

The victim was reportedly at the property for a plumbing job.

"We ring first if we know there are dogs on site, they are supposed to be restrained before we enter," colleague Darren said.

The three dogs were seized and put down on Friday afternoon, an impounding officer at The Hills Shire council said in a statement.

One of the dogs had been subject to a nuisance order.

"One of the dogs is subject to a previous nuisance order to prevent it from wandering - however this attack occurred on the property," the statement said.

Friday's attack is the latest in a spate of NSW dog attacks.

An 81-year-old woman remains in hospital after an attack by two American Staffordshire terrier crosses on Monday that left her with serious cuts to her face and body.

Four other people - two men and two women - who came to her aid were also bitten.

In a separate attack an eight-year-old boy was taken to hospital for a suspected fractured forearm and bite marks after he was bitten by a dog on August 28 in Edgeworth, near Newcastle.