Four people, including a police officer, attacked by two dogs in Sydney's west

Four people have been hospitalised after being attacked by a pair of dogs in Sydney's west this morning.

A man was walking his mastiff-staffy cross and staffy-cattledog cross on Charles Hackett Drive in St Marys at 10am when, according to witnesses, one of the dogs charged at a nearby woman.

The animal latched onto her arm and dragged her to the ground.

READ MORE: Police officers charged with negligent manslaughter of tradie

The woman, aged in her 70s, was left with injuries to her ear, arm and neck.

The man tried to intervene when the dog turned on its owner.

The canine latched onto his shoulder and neck, causing significant injuries to his face.

READ MORE: Who was Charlie Kirk? Conservative figure who helped build support for Trump among young people shot dead

The commotion caught the attention of drivers in nearby traffic, including a man in his 30s who tried to pull one of the dogs off the owner.

The dog started to attack him and he was left with arm injuries.

A police officer who tried to secure the dogs was also attacked.

It is understood the undercover officer used his foot to distract one of the dogs before the canine latched on.

One witness said multiple people tried to secure the dog which "just didn't stop".

"It kept on going and going and going," she said.

"It took six men to pin it down with an umbrella in its mouth to stop biting, police pepper-sprayed it."

READ MORE: Winds over 100km/h to batter state as rain recedes

Another witness was left shocked as he saw the dog attack the woman.

"I was pretty much sitting there thinking 'do I get out of my car? Do I go and help him? What's going on?'," he said.

The dogs were eventually secured by police at the scene before they were taken by Penrith City Council rangers.

"Staff transported the dogs to the Hawkesbury Animal Shelter, where they will remain while police investigations are ongoing," a council spokesperson said.

The incident comes after 17-year-old Annalyse Blyton died in hospital after she was attacked by a dog in the NSW town of Singleton earlier this month.

DOWNLOAD THE 9NEWS APP: Stay across all the latest in breaking news, sport, politics and the weather via our news app and get notifications sent straight to your smartphone. Available on the Apple App Store and Google Play.