A car crashed into a Melbourne school on Tuesday. Here's everything we know.

A boy is dead after a woman crashed through a primary school fence and into a group of students, in what police described as a "tragic accident".

The 40-year-old driver had just collected her child at Auburn South Primary School, east of Melbourne, when she performed a U-turn on Burgess Street.

She crashed through the fence into a table where the five children were seated during afternoon recess, police say.

An 11-year-old boy suffered critical injuries in the collision, just after 2.30pm on Tuesday, and later died.

Two 11-year-old girls, a 10-year-old girl and a 10-year-old boy were seriously injured and taken to hospital. They remained in a serious but stable condition overnight.

The driver was arrested and interviewed by police, Inspector Craig McEvoy said. She has since been released, pending further enquiries.

A spokesman for the Department of Education told the ABC that the driver of the car was believed to have suffered a medical episode. Meanwhile, police have said it's too soon to determine the reason for the crash.

"It appears it is a tragic accident," Insp McEvoy told reporters at the scene. The woman and her child were not injured.

"From the community [to] the school community, the locals, the first responders, ambos, police — it's really tough," he said. "These events are always hard where there's death and serious injury, but especially difficult when there's children involved."

The leafy street was closed off as officers assessed the area of impact.

As of 6pm on the 29th, more than a dozen police officers remained at the scene working on the white vehicle which was lodged past the school's grey steel fence in front of a picnic table.

Police took statements from the school principal, teachers, parents and other witnesses. The car had a green P-plate, but Insp McEvoy said he was not certain of the woman's licence status.

Ambulance Victoria sent multiple advanced life support and mobile intensive care vehicles to the scene.

Three of the children were taken to the Royal Children's Hospital and two were taken to Monash Medical Centre.

Parent Lucy told radio station 3AW that her son was friends with some of the grade five students and possibly a prep student hit by the car during recess.

"We got a text message from the school just saying that Burgess Street closed and then we... actually drove past, and I just saw one police car," she said.

"Then we just started hearing more and more police cars go down."

Lucy said she arrived at the scene to find parents hugging their children and each other.

"It's just every person's worst nightmare," she said.

Premier Jacinta Allan posted her condolences on social media, saying it had cast a "dark shadow" over the city.

"I'm sending my love and thoughts to the students, their families and the whole school community. And my thanks to the first responders on the scene," she said in a post on X.

Education Minister Ben Carroll said: "What happened yesterday was every parent's worst nightmare. We extend our sincere sympathies and heartfelt condolences to the family of the student who lost his life.

"This is a terrible tragedy. At times like this, school communities do come together."

Victorian Opposition Leader and Member for Hawthorn John Pesutto said the incident came as "a painful shock".

"Auburn South Primary is an outstanding local school with a tight-knit community of students, teachers, parents and friends, and this incident will come as a painful shock," he said.

The Department of Education said in a statement it was working closely with staff, students and parents of the school to support them.

Auburn South Primary School will reopen today with extra support. The school will reopen on Wednesday, with extra support available for those who need it.

Feature image: AAP.