Bankstown boy critical after schoolyard game 'popular and happy'

The mother of a 10-year-old Sydney boy critically injured in an apparent game gone wrong says her son is "happy and popular" at the school.

Nedal Chemaisse is in a critical but stable condition after being rushed to The Children's Hospital at Westmead following an incident at Wattawa Heights Public School in Bankstown just after midday yesterday.

Nedal was pushed in the back by a classmate during a play-fight, which sparked a life-threatening medical episode.

Nedal is understood to have a pre-existing medical condition.

His mother Rana Zahed Chemaisse today thanked first responders for saving her son's life. 

"We are grateful for the quick response from the school, paramedics and the NSW Police for the all their efforts for saving my son's life," she told 9NEWS.

"We've never had any issues with fights or bullying and I'm not sure of what has happened to escalate to this serious matter.

"I want to emphasise that he is a happy and popular child at the school and we've never had any problems there."

A spokeswoman for NSW Police confirmed an investigation had been launched.

"At this stage we are looking into everything," she said.

A child cannot be charged with a criminal offence in Australia if they are under the age of 10.

Officers from Bankstown Police Area Command have spoken with the students involved.

Police said the boy's condition will be monitored but no further action is expected to be taken over the matter.

Wattawa Heights Public School said it was supporting the family of the injured and assisting police with their investigation.

"When accurate information about what occurred is available, the school will share that with parents and carers," a spokesperson told 9NEWS.

The public school's playground was turned into a crime scene as forensic teams sealed off the change rooms and pupils were led back to class in a single file.