Passengers and crew aboard a Virgin Australia flight out of Melbourne have reportedly had to restrain two men in a “terrifying” onboard incident.

The commotion began aboard Qatar Airways-operated flight VA7 bound for Doha, when two men allegedly began assaulting staff on Friday afternoon.

Witness accounts allege that flight attendants were subjected to spitting and headbutting and that the men made threats about using a gun.

Passengers and crew aboard a Virgin Australia flight out of Melbourne have reportedly had to restrain two men in a “terrifying” onboard incident. NurPhoto via Getty Images

Up to seven people and zip ties were reportedly needed to restrain each of the men.

They were handed to local authorities in Doha, who boarded the plane upon arrival.

One witness described the incident, which happened to take place on the 25th anniversary of the September 11 terror attacks, as “very scary” and said authorities were met with applause when they boarded the flight.

“Really big props to the Qatar flight attendants, they were hands on for about 10 hours straight,” the witness told 3AW’s Jacqueline Felgate. “They really couldn’t do too much more.”

Another witness said the events were “terrifying,” and added it was “disgraceful what the poor flight attendants had to deal with.”

The commotion began aboard Qatar Airways-operated flight VA7 bound for Doha, when two men allegedly began assaulting staff on Friday afternoon. NurPhoto via Getty Images

In a statement, Qatar Airways told news.com.au: “We can confirm that two male passengers were involved in a physical altercation on board flight VA7 from Melbourne to Doha, operated by Qatar Airways.

“Both passengers were restrained and, upon arrival in Doha, were handed over to local authorities.

“The safety and wellbeing of our crew and passengers remain our highest priority.”

The Australian Federal Police and Virgin Australia were contacted for comment.