By Mibenge Nsenduluka in Melbourne

POLICE are investigating whether a truck driver who was charged over a bus crash that left multiple children seriously injured was distracted in the lead-up to the Melbourne collision.

The 49-year-old man was charged with four counts of dangerous driving causing serious injury on Wednesday and he will appear in Melbourne Magistrates Court via video link.

Victoria Police Superintendent Michael Cruse said investigators were trying to establish what caused the crash.

“Inattention is something that we are actively looking at as part of the investigation,” he told reporters.

One child remains in intensive care and several have suffered complete or partial amputations after being severely injured in the Tuesday crash.

Ten children aged five to 11 sustained traumatic or serious injuries when the school bus carrying 45 kids collided with a truck and rolled on its side about 3.40pm.

The male bus driver sustained minor injuries.

Students from Exford Primary School were going home when a truck hit the school bus from behind at Eynesbury, 44km west of the Melbourne city centre.

A Code Brown, an emergency response for hospitals anticipating mass casualties, was declared at Melbourne’s Royal Children’s Hospital after the crash and ran until 8pm.

Specialist doctors were called in to perform emergency surgeries after nine children were admitted.

Several were trapped inside the bus before witnesses and emergency workers pulled them from the wreckage and took them to hospital.

Parents faced an anxious wait overnight before finally being reunited with their children early Wednesday morning.

Seven children are still in a serious condition, with four undergoing surgery overnight, one in intensive care and another two going into theatre on Wednesday.

Three patients are receiving spinal support.

Multiple surgeons are in attendance including the hospital’s own doctors and vascular and specialist microplastic surgeons from Royal Melbourne Hospital.

Many of the children will need to undergo multiple surgeries and long-term rehabilitation therapy is likely to be needed.

Counsellors are going to Exford Primary School to help students process the tragedy.

Prime Minister Anthony Albanese said the crash was horrific.

“My heart goes out to them and to their families at what must be an extraordinarily difficult time,” he said.

Premier Daniel Andrews said he had been in contact with the school.

“The reason I called (the school’s principal) last night and again this morning was just to make sure that she knew and understood that ‘whatever you ask for … the answer will be yes. We’re there for you’,” he said.

Victorian Education Minister Natalie Hutchins said the school would remain open with mental health support workers on the ground to assist traumatised students.

“Particularly those kids who were involved in the accident but also those children that would have seen the accident last night … on TV, on social media,” she said.

• Lifeline 131114
• Kids Helpline 1800 551800 (for people aged 5 to 25)