FIRST ON 7: Police are becoming increasingly worried about attempts to snatch children from western Sydney's streets, with three youngsters from one family the latest targets.

The trio managed to get away from a man and a woman who were trying to abduct them, but the attempt has left them and their parents rattled.

Police are warning, as Christmas holidays get underway, that all children and their parents need to be extra wary of strangers.

We won't identify this father to protect his children, who were almost snatched from a Colyton street.

"How would you expect a creature like that would take your kids so close to your front door,” he said.

His three children, the youngest nine-years-old, were playing on their scooters when a woman sitting in the passenger seat of a car yelled that she'd "get them".

“A door opened up while the car was driving midstream and they tried to drag my daughter in,” the father said.

The children ran screaming back home where their parents called police.

“We believe it’s a one-off incident, but regardless of that we'll treat it very seriously,” Penrith police inspector Gary Sims said.

In just over two weeks, 13 threats to child safety have been reported, including several arrests for assaults on children. Most were in Sydney, but some also stretching from Toronto to Mittagong.

Detectives say some reports are baseless, but all are taken seriously.

Heading into the Christmas break, police don’t want kids to stop being active out and about, but they do want them to be aware of the important messages about how to stay safe.

“If someone does grab you, scream out loudly go away I don’t know you,” John Kerlatec from the Sex Crimes Squad said.

“I don’t want to worry parents, all I want to do is raise awareness.”

Police say children shouldn't talk to people they don't know, and they need a safe place nearby they can head to if they’re in danger, and always tell a trusted adult.