A woman has reportedly driven in to the Brisbane Airport airfield after smashing through a fence on Tuesday night.
All flights in and out of the airport were suspended for about two hours because of the major security breach.
Australian Federal Police said a 37-year-old woman had been taken to hospital following the incident.
"The AFP is continuing to conduct enquiries into this matter. Further information will be provided in due course," the AFP said in a statement.
They said media reports that multiple people were in the vehicle were untrue.
Initial reports also said the car had reached the tarmac, but Brisbane Airport later stated that the vehicle had only made it to a section of the airfield and not the runway.
Around midnight, the airport tweeted that the runway had reopened and flights were set to resume.
UPDATE: Our runway has reopened. Flights will resume soon. Thanks for your patience this evening.— Brisbane Airport (@BrisbaneAirport) July 8, 2014
Earlier, it reported all flights had been halted, and later advised passengers to check with their airlines for schedule changes.
An airport spokeswoman said seven flights were diverted, mainly to the Gold Coast. There were also 17 flights that were significantly delayed.
The AFP is currently responding to a security matter airside. Until resolved all flights will be held. Further flight updates to come.— Brisbane Airport (@BrisbaneAirport) July 8, 2014
On Wednesday, Brisbane Airport Corporation issued a statement to assure passengers the airport was a safe and secure facility.
“The systems and processes in place at Brisbane Airport comply with Federal Government standards however, with Brisbane hosting the G20 in November, BAC is progressively increasing its security to even higher levels, general manager operations Stephen Goodwin said.
“We are currently in the middle of a major upgrade of the airfield perimeter and have already spent $2 million upgrading the fence line, with at least that much to go before we finish current works.
“Airport security requires a multi-layered approach and the rapid response to last night’s incident is evidence that our security response and procedures work. It was contained quickly by police and emergency personnel and additional precautions were taken to ensure there were no other threats to the public.''
Mr Goodwin said the corporation would continue to assist authorities investigating Tuesday night's incident.
"And the results of these investigations will determine if we need to make any changes to our preparations for hosting the G20,'' he said.
“We cannot and do not comment on specific security measures.”
The Brisbane Airport Corporation has called a press conference for noon.
- with AAP