Police arrested a man in his 60s and escorted him to hospital with serious burns on Thursday after he allegedly lit the inside of his car on fire and drove into the roller door of the police station car park. In a late-night press conference, Assistant Commissioner Dennis Clifford said there was nothing to link the incident to terrorism, but the station had been on "high alert".

"The police are on high alert and we've been that way for some time due to events here and overseas," Assistant Commissioner Clifford said.

"This is a serious incident... it's a miracle nobody else was seriously hurt."

It is believed the station was fortified after police became aware of a threat to "shoot up" the building late last year, but it's not known if the renovations helped to stop the car from gaining access. Photos from the scene showed the light-coloured Hyundai Getz wedged underneath the police roller door, which was bent and significantly damaged.

All doors of the hatchback were open including the boot, and one of the car's windows appeared to be smashed, as police continued to guard the scene. Police believe some sort of accelerant was used to set its interior alight.

In November, a student from Arthur Phillip High School – the same school attended by 15-year-old Farhad Jabar, who shot dead police accountant Curtis Cheng – was charged after allegedly making threats against the police station. The teenager allegedly posted on social media "merryland [sic] police station is next hope they all burn in hell" and "them lil piggies get shot".

In December, a man from Merrylands joined six others who were charged over an alleged plot to target police buildings. His home had been raided by police two times in just over two years. Numerous threats have also been made against the station, News Corp reported, with several officers followed home by people with suspected crime links.

It is thought the station is a target of ire because its officers contribute to operations including police raids.

Police security has been tightened around the state after several incidents, including the targeting of police headquarters, with officers advised to wear their weapons even when leaving the station to get lunch.