The two young children killed in a horror crash on a highway in Sydney’s southwest have been identified, as their distraught parents say the forgive the driver involved in the crash.

Katherine, 5, and her 14-month-old brother Harry were struck and killed by a car in Cabramatta on Wednesday afternoon.

Emergency crews were called to the intersection of Joseph and Gilbert St about 3.15pm where they found members of the community performing CPR on the pair, after first lifting a car in order to free one of the children trapped underneath.

Multiple paramedic and medical crews worked to treat Katherine and Harry’s injuries at the site of the crash, before the children were rushed to The Children’s Hospital at Westmead in a critical condition.

However, their injuries were too severe and they could not be saved.

Speaking outside their Cabramatta home on Thursday, the children’s mother, Sok Ram, and father, Vundy Tha, said they “cannot believe” their children are gone.

“Why did my kids die? I hope (the car) would hit me, not my baby,” Ram said.

Ram, 33, said she had been pushing Harry in a pram and crossing the road with Katherine when they were hit by a car she had thought slowed down to let them cross.

The driver, a 56-year-old man, was uninjured and was arrested before being taken to hospital for mandatory testing. He has since been released.

Ram, who was was treated for minor injuries at the scene, said she forgave the driver, but pleaded for other drivers to “please look, be careful before you go”.

Tha said he was not there when his children were hit, but received a call and raced to the scene, thanking members of the community who tried to save them.

“I would like to say thank you for everyone … I wasn’t there, thank you to everyone,” he said.

Tha also said he forgave the driver, because blaming him would not bring his children back.

“Even the driver, I forgive him already,” he said.

“Nothing can change, you know? Nothing can change. I couldn’t get my kid back.”

A fundraiser created to support the family said the two children “had their lives taken in a split second”.

“I am absolutely devastated,” GoFundMe organiser Patrick Te said.

“Their mother, Sok, was picking up Katherine from school. Katherine, who was in her first year of kindergarten, was excited to go home after just receiving an award.

“As they were crossing the road together, heading back to the car, an oncoming vehicle suddenly struck both Katherine and the pram where Harry was sitting.

“A mother not only lost a child — she lost both of her children, her only two children.

“As I sit here at Westmead Children’s Hospital looking at these two precious souls and their mother, it is extremely difficult to comprehend.

“As a parent myself, I cannot even begin to fathom the long road ahead for both the mother and father. Regardless of who is at fault, their journey to recovery will be incredibly difficult.”

Acting Superintendent Timothy Calman said on Wednesday that it was a difficult scene for everyone involved.

“It’s probably one of the most confronting scenes that police come across, dealing with young children,” he said.

“It’s tragic circumstances for the family.”

Calman said the driver of the car was not known to police nor the victims.

Te said the fundraiser was created to “help support this family who has been through the unimaginable”.

Investigations into the cause of the crash are ongoing.