A near 2-hour standoff at Shanghai's Hongqiao Airport ended peacefully yesterday afternoon after a plane crew refused to take off with an armed passenger on board.

Chartered by Air China, the Dragon Air Airbus A330 from Hong Kong was about to fly from Shanghai to Beijing when crew discovered the passenger, a security officer, was carrying a gun.

"We were sitting waiting to take off and were already a bit delayed when we heard some people arguing further up the plane," a passenger, who asked not to be named, told China Daily.

"The man said he was allowed to carry his gun on internal flights within the Chinese mainland because of his job, but because the plane and the crew were from Hong Kong and follow different regulations, they said they would not fly with the gun on board."

The plane, flight CA1832, carrying around 300 passengers, was originally scheduled to leave at 10.35 am.

As the delay stretched past the hour mark, a negotiator was sent on board to reason with the belligerent security officer.

Turning down a suggestion to take the bullets out of his gun and allow the crew to look after them for the duration of the flight, the man refused to give up his weapon.

"We couldn't really see what was going on so we just had to sit there for 2 hours while people argued and worked out what to do," the source said.

"Eventually the captain refused to fly to Beijing with the man on board and he had no option but to get off and catch another flight.

"I wasn't scared, I just thought it was ridiculous that this one guy should hold up the flight and keep everyone waiting."

Having unloaded the officer and his gun, the flight eventually took off at 12:19 pm, arriving safely in Beijing around 2 hours later.

When China Daily asked Air China staff at Hongqiao Airport about the delay they initially said the plane had been delayed only 25 minutes.

Another employee, who would not give his name, later confirmed the 110-minute delay but said he did not know why it had occurred.

Police at the airport also claimed ignorance of the drama, which had unfolded on the asphalt just metres from their station.

As for who, if anyone, is allowed to carry arms on internal flights on the mainland, China Daily received conflicting reports.

Xu Zhihui, an officer on duty at the airport passenger security check, said his department had strictly followed all rules and insisted a passenger could only have passed through carrying a gun if he had the necessary certification.

But Xu would not be drawn on exactly what criteria had to be met for someone to carry a gun on board, saying: "A lot of security information is secret and this is confidential because it concerns security officers, not the general public."

He blamed Air China for the mix up, but staff at the airport headquarters and air safety department admitted they were unclear who was allowed to carry arms on a flight and what the relevant security procedures were.

However, another officer with the public security bureau at the airport told China Daily that, according to rules set by the Beijing-based General Administration of Civil Aviation of China, no passengers are allowed to carry weapons on to the plane or pack firearms in their luggage, whoever they are.