Police have confirmed they believe a leaking gas canister is to blame for an explosion outside a school in Canberra that killed a father.

The dad died yesterday just after 5pm when a car exploded outside the school - he's being remembered as "a down-to-Earth, good bloke", with families laying flower tributes on the school fence in his memory.

The St Clare of Assisi Catholic school in Conder, in the city's south, will remain closed until Monday after the 50-year-old man was killed while picking his child from after-school care.

St Clare of Assisi Catholic school Principal Matthew Egan-Richards has remembered the father killed in a carpark explosion as a 'down-to-Earth good bloke' Picture: 9NEWS. (9NEWS)

ACT emergency crews were called to the school to reports of a vehicle explosion and found the man in a critical condition. Paramedics treated the man at the scene before he was taken to hospital where he later died.

Police believe a leaking gas canister could be to blame for the explosion.

The school's principal Matthew Egan-Richards today told reporters the father was well-known in the local community and at the school.

Debris can be seen near the blast location at the primary school. Picture: 9NEWS (Nine)

Police have not yet said what caused the explosion. Picture: 9NEWS (Nine)

Flower tributes are left on the school fence. Picture: 9NEWS (nine)

The 50-year-old man was picking up a child from after-school care from St Clare of Assisi in Conder, in the city's south, just before 5pm yesterday. Picture: 9NEWS (Nine)

"He was certainly known in our school community and liked. I knew him and his family," he said.

"He was a down-to-Earth, good bloke. Lovely family, very supportive of the school and very involved in their community."

The school posted on its Facebook page last night that it would be closed until Monday, with Mr Egan-Richards emailing parents and carers confirming the news.

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"It is with deep sadness that I need to let you know that following an incident in the school carpark today, one of our parents has passed away," the email read.

"At this difficult time, we pray for the family and friends. We will offer all the support we can in the coming days and weeks."

Mr Egan Richards also told reporters that, while the school is looking into providing ongoing support for students, families and staff affected by the incident, the community response has been "heartening".

"The contact that I have had from the Catholic Education Office, from all our parents in the community, from the principals of all our Catholic schools - but the way our families work together has been very heartening," he said.

"Our after school care staff did a great job of lock down, they isolated the children and took are of them.

ACT Policing and WorkSafe ACT are investigating. Picture: 9NEWS (Nine)

"That begin said, Monday we will be looking at the need of those kids and providing as much support for them as we can as well as their families and the staff.

Many people have left comments on Facebook sharing their disbelief and shock at the incident.

"Thoughts and prayers to all involved," one person wrote.

Local resident Hailee Williams said she felt her house shake from the impact of the explosion. Picture: 9NEWS. (9NEWS)

Local resident Hailee Williams said that she was at home at the time of the explosion and felt her entire house move because of the impact of the blast.

"I thought the car might have blown up - the whole house shook - and it was just this huge bang and it made it sound like it was right here," she said.

"It's devastating and hard to think that happened just down the road... There's still lots of questions. Everyone's still like, 'what happened? How did it happen? Why did it happen?

"I think that its devastating. I think that the school has done the right thing by closing down for the day and our hearts just go out to anyone who was there or witnessed it."

A hole could be seen in the side of a white ute in the car park of the school, while a number of people in the area reported hearing the blast and felt their windows rattle.