A mid-air security incident on board an Air Mauritius flight has forced the plane to return to Melbourne Airport.
Emergency services were called to Tullamarine at 2.38pm after reports of an incident on a flight carrying 197 people bound for Mauritius via Perth.
An Air Mauritius spokeswoman confirmed a suspicious item was discovered on board the aircraft.
An MFB spokeswoman said 13 trucks had responded to the incident after the police asked them "to respond to a possible full emergency".
A Melbourne Airport spokeswoman said passengers on the plane had been evacuated but there was "no danger posed to people within the terminals or wider airport precinct".
The MFB spokeswoman said the plane had landed and would be taken to a remote part of the airport under the direction of the Australian Federal Police.
She said MFB and CFA crews were at the scene but there had been no fire reported.
The captain of Air Mauritius Flight MK943 reportedly turned the flight around over Mount Gambier after declaring an emergency.
The Melbourne Airport spokeswoman denied reports all flights had been grounded, but said passengers should expect some delays.
An Australian Federal Police spokeswoman said the incident was ongoing and police were working with airport staff and the airline to ensure all passengers evacuated the plane safely after the security incident.
She said there had not been any threat to the public and the Airbus A340 had landed at 2.50pm.
No further details were available as the incident was "still happening", she said.