A father has spoken out after an alleged drunk driver crashed into a group of children, killing four and leaving another in a critical condition in Sydney’s northwest on Saturday night.

“Yesterday I lost three of my children,” Danny Abdulah told reporters.

“I don’t know what to say.

“I’m numb.”

A group of seven kids - including Abdulah’s children Antony, 13, Angelina, 12, and Sienna, 9 - were riding on the footpath on their way to buy ice cream at the time of the crash.

Four children have died and a fifth is in a critical condition after they were hit by a 4WD while riding bicycles in Sydney’s northwest. Credit: 7NEWS

Four children died at the scene - three of which were Abdulah’s son and two daughters.

The fourth, aged 11, was their cousin Veronique Sakr.

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.

‘Be careful’

“All I want to say is drivers be careful,” he said.

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

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The male driver, 29, was arrested at the scene 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.

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He has 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.

His case was on Sunday heard at Parramatta Bail Court. He did not appear in court and did not apply for bail, which was formally refused by magistrate John McIntosh.

He’s scheduled to return to Parramatta Local Court on April 2.

- With AAP