An alleged drink-driver has been charged with manslaughter and more than a dozen driving offences after four children died and a fifth suffered serious injuries when they were hit by a car on a western Sydney footpath.

Three of the children killed in Saturday night’s incident near Parramatta were siblings and the fourth, aged 11, was their cousin.

Danny Abdallah, the father of the three siblings aged 8, 12 and 13, told reporters on Sunday he was heartbroken.

“I don’t know what to say. I’m numb, probably that’s what I feel at the moment. All I want to say is please, drivers, be careful,” Mr Abdallah said.

“These kids were just walking innocently, enjoying each other’s company … and this morning I woke up and I have lost three kids.”

Police at the crash site do what little they can to comfort a man believed to be the father of the dead children . Photo: TNV

The male driver, 29, was arrested on Saturday night after returning a positive result in a roadside breath test and taken for a breath analysis.

He allegedly recorded a blood alcohol reading of 0.150 – three times over the limit – and has now been charged with four counts of manslaughter as well as dangerous driving occasioning death, dangerous driving occasioning grievous bodily harm, negligent driving, drink-driving and other offences.

He was refused bail to appear at Parramatta Bail Court on Sunday.

Emergency services were called to Bettington Road in Oatlands before 8pm on Saturday but four of the children died at the scene, police said.

A fifth child, 11, was taken to The Children’s Hospital in Westmead in a critical condition but is now in a serious but stable condition. Two other girls, aged 10 and 13, suffered minor injuries.

"Please, just make sure you love your loved ones, your kids especially, because you don't know when…" – Daniel Abdallah's emotional plea following an overnight tragedy where four children were killed, and one critically injured, in Oatlands. https://t.co/YENZK9oh3j #7NEWS pic.twitter.com/zt1E4tR4kc

— 7NEWS Sydney (@7NewsSydney) February 1, 2020

The group of seven children had been travelling on the footpath and were on their way to buy ice cream when police believe the four-wheel drive mounted the kerb and hit them.

NSW Ambulance Acting Superintendent Andrew McAlpine on Saturday evening said paramedics had arrived to a horrific scene.

“This is incredibly hard for the emergency services notwithstanding the losses that the families have sustained,” Mr McAlpine told reporters.

“It’s very, very difficult for police, for fire rescue, for paramedics to be confronted with such chaos and carnage.”

Police said the family were at the hospital with relatives.

“They’re obviously very distraught and under these circumstances we can’t provide much information to them at this stage so that’s difficult for them,” Acting Assistant Commissioner Jason Joyce said.

Distraught members of the Oatlands community on Sunday placed flowers at the scene of the tragedy.

-with AAP