A security alert at Melbourne’s Tullamarine Airport has forced the evacuation of a terminal building and disrupted some flights.

The Tigerair terminal was closed about 9:00pm (AEDT), a spokeswoman for the airport said.

“We are responding and working with the relevant authorities over a security alert that was directed at Tigerair,” the spokeswoman said.

She said some Tigerair flights had been disrupted but all other operations at the airport were continuing as normal.

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

He also tweeted that passengers were told some planes were disembarking but “we’ll be on ours for a lengthy amount of time”.

Victoria Police said an incident was ongoing at the airport and they were investigating the matter.