The man who blew up a van packed with gas cylinders into the Christian lobby office in Canberra was not driven by a political, religious or ideological motive, police said.
"His actions were not politically, religiously or ideologically motivated," a spokesman for the Australian Federal Police said in Canberra.
No arrests have been made yet and the driver remains in a critical condition.
The spokesman said his condition meant interviews with the driver were limited but offered scarce detail into the investigation.
An ACT Police spokesperson said earlier that "Investigations into a vehicle fire at the Australian Christian Lobby and no one was injured inside the building."
A van packed with gas bottles has exploded outside the Australian Christian Lobby's Canberra office. Photo: Twitter
The car bomb that exploded inside the ACL's Canberra office was deemed a "targeted attack" on free speech by the group's managing director.
Windows were blown out and furnishings have been destroyed at the office in Deakin after it was rammed by a van about 10.45pm on Wednesday.
Police said the driver was a 35-year-old Australian living in the ACT who took himself to to Canberra Hospital with serious burn injuries.
ACL managing director Lyle Shelton said they won't be silenced by the suspected car bomb that followed a year of death threats.
"I'm sure it's a message to intimidate us and cause us to be silent in the public square and that's something we're not prepared to do," he said.
"It's more important than ever that we have our voice involved in the public discourse."
The gas bottles didn't explode. Photo: 7 News
Mr Shelton said they have received multiple threats over its opposition to gay marriage and the Safe Schools program that aims to reduce bullying of gay students.
One of those threats was tracked to a person in Tasmania but the rest were unable to be tracked, he said.
"This is not the Australia that I grew up in," Mr Shelton said at the scene on Thursday.
"There is no doubt in my mind that ACL was the target."
"Obviously we don't know the motives of the person who drove this van, but we have received a number of death threats and threats of violence over the course of this year that we have reported to police."
"The burnt out van was cordoned off with police tape. Photo: Twitter
He blamed the left side of politics for potentially fuelling the attack, saying its "name-calling" during the gay marriage debate was unhelpful.
The Eternity House building on Campion Street had, for the first time, needed to be locked for most of the year, amid heated debate over the same-sex marriage plebiscite and calls for the Safe Schools program to be axed.
"When members of parliament, particularly on the extreme left, refer to us in the parliament as hate groups, as bigots, I'm sure that doesn't help the situation," he said.
"If there are people who are a bit unhinged out there, that sort of rhetoric doesn't help. As a society we've got to have civil debate, we've got to stop the name calling and the slurs."
Mr Shelton tweeted two pictures early on Thursday morning showing a burnt out van rammed into the front of the office building.
"A vehicle has rammed our office in Canberra & exploded. All Staff are safe. I do not know the condition of the driver. Prayers appreciated," Mr Shelton tweeted, with a picture showing a burnt out van cordoned off with police tape.
A second tweet from Mr Shelton showed the van more clearly and said: "A closer view of the car bomb driven into the ACL office in Canberra tonight. Shocked that this could happen in Australia."
An ACT Police spokesperson said there will be "investigations into a vehicle fire. Photo: 7 News
Pauline Hanson described it as a "cowardly attack" while coalition backbencher George Christensen also took to Twitter saying if the attack was politically motivated, "it is disgraceful and should be denounced".
Police said the driver's actions were not politically, religiously or ideologically motivated.
An ACT Police spokesperson said: “Investigations into a vehicle fire at the Australian Christian Lobby and no one was injured inside the building."