A terminal at Melbourne Airport was evacuated on Friday night following a threat that was reportedly made against Tigerair.
The incident happened at about 9pm, reported Malaysian wire agency Bernama.
Australian media ABC News reported that all outbound flights were grounded and inbound flights were redirected to another part of Terminal Four, which was specifically for Tigerair.
The terminal was declared safe at about 5am on Saturday, local time - eight hours after the incident was first reported - and the normal operations have resumed, according to ABC News.
While Melbourne Airport spokeswoman Anna Gillett would not provide an exact reason for the shutdown, another publication The Age reported that the threat was related to a plane that was on the runway and the surrounding area. Gillett said the airport never releases details on security issues, reported Bernama.
The Age reported that three inbound Tigerair planes were evacuated on the runway and passengers were transferred to buses which took them to the terminal.
Tigerair Australia chief executive Rob Sharp in a statement said: "Tigerair takes all security related alerts extremely seriously".
"All necessary steps were taken by the airline to quickly involve the relevant authorities and implement precautionary measures to ensure passenger safety," he said.