22/12/2016 11:29 AM AEDT | Updated 22/12/2016 5:26 PM AEDT

Van Explosion Ruled 'Not Politically, Religiously Or Ideologically Motivated'

The Christian lobby earlier described it as a 'car bombing'.

Lyle Shelton managing director of the Australian Christian Lobby in his burnt out office.
Andrew Meares/Fairfax
Lyle Shelton managing director of the Australian Christian Lobby in his burnt out office.

CANBERRA -- The dangers of jumping to conclusions about violent acts have been quickly exposed Thursday after a van explosion at the Canberra headquarters of the Australian Christian Lobby (ACL) has been ruled out as deliberate "car bombing" or terrorism.

Investigations are still underway into the fiery destruction of a van containing gas cylinders after it was exploded late on Wednesday night at the front door of the ACL's headquarters, just several kilometres from parliament house.

Investigating police have established the driver ignited the gas cylinders with an unknown motivation

"We have established that the actions of this individual are not politically, religiously or ideologically motivated," Deputy Chief Police Officer Commander Mark Walters told reporters.

Andrew Meares/Fairfax
The scorched car park at the Australian Christian Lobby in Canberra.

Damage to the building is extensive with the glass door melted, windows blown out, the roof unstable and the area scorched. The van has been removed by police, but melted tyre matter remains in the car park.

ACL's managing director Lyle Shelton had earlier and quickly leapt to the conclusion it was a "car bomb" and tied it to previous death threats and threats of violence over the lobby group's vocal stance against same sex marriage and the safe schools program.

Following the police statement, Shelton told ABC News "as much as I obviously respect the police and the work they do, I'm a little bit sceptical".

"This seems too much of a coincidence [that] this could be solely the motivation of someone who was just acting without any targeted motive. He was pulled from a burning wreck when he gave that statement. He has grievous injuries."

One Nation Senator Malcolm Roberts also decried the events, tweeting: "terror has come to our shores".

Investigators have confirmed a 35-year-old Canberra man and Australian national -- not previously known to police -- had crashed into the building, igniting gas cylinders in the van and causing an explosion.

The 35-year-old man is in a critical condition at Canberra Hospital with serious burns.

After briefly speaking to the man, police ruled out terrorism saying his "actions were not politically, religiously or ideologically motivated".

After being repeated asked by reporters on the scene about the drivers's alleged motivation, Commander Walters could only say: "Our investigation is ongoing to establish the full circumstances of this particular incident."

Investigations are ongoing.

"Any future interview with the gentleman will be subject to his medical condition," Commander Walters said.

Andrew Meares/Fairfax
The melted front door of the Australian Christian Lobby in Canberra
Earlier, Shelton stated the incident was a "car bombing" or a "detonation," and also an "attack on free speech".

"I am sure it is a message to intimidate us and cause us to be silent in the public square," he told reporters on the scene.

"And that is something that we are not prepared to do."

Shelton did say it was too early to state what caused the incident, but he then gave what he called "context".

"I stress I don't know the motivation of last night's attack," he said. "But in the context of the threats we have already received it is deeply unsettling.

"I never thought that in coming to work for a public advocacy organisation like ACL that we'd suffer from this sort of thing.

"This is not the Australia I grew up in."

Police say they will be conducting a thorough investigation including previous threats to the Australian Christian Lobby.

The community is being reassured by police that there is no concern for public safety.

"I want to reassure the members of the Canberra community that ACT Policing is working very vigorously to fully understand the circumstances of this incident, but we do not believe there is any threat to the community as a result of this particular incident," Commander Walters said.

Shelton earlier said he had "no malice" for the man receiving care in hospital and also offered him "hopes and prayers.