Security threat over at Melbourne Airport

Melbourne's Tullamarine Airport. Photo / Getty Images

A security alert is over at Melbourne's Tullamarine Airport after a threat was directed at Tigerair Australia, forcing the evacuation of passengers from a terminal and the cancellation of flights.

The incident means there will be flight delays throughout the day.

The threat was received around 9pm on Friday resulting in the evacuation of Tigerair's terminal 4 and flight cancellations.

Tigerair Australia CEO Rob Sharp said all necessary steps were taken by the airline to implement precautionary measures and ensure passenger safety.

He thanked Australian Federal Police and Victorian police who were sent in to search the terminal following the threat.

"Tigerair also apologises to affected passengers for the inconvenience and is doing everything possible to get them to their destinations as quickly as possible," Mr Sharp said.

Victoria Police are investigating. Police would not confirm the nature of the security threat but some on Twitter claiming to be passengers mentioned a possible bomb threat.

Scott Marquardt, who said he was on board a Tigerair flight from Brisbane that landed around midnight, tweeted saying the crew had announced they would be on the tarmac for at least another hour.

To answer your questions, I'm on TigerAir flight 539. Announcement of POSSIBLE bomb threat at Melbourne airport made by flight crew

— Scott Marquardt (@MarquardtScott) January 9, 2015

- AAP