Increasing number of in-flight thefts being reported not only in short-haul but also long-haul flights.

A Turkish businessman has lost HK$2m (£258,000) worth of cash and valuables from his hand luggage stored in an overhead cabin compartment during a flight from Dubai to Hong Kong. This is believed to be one of the biggest in-flight theft reported so far.

Mustasa Saci, a Turkish watch merchant, only realised the cash and valuables missing after he had disembarked when the plane landed at the Hong Kong International Airport. He sought help from airline staff who called police.

According to the South China Morning Post, there has been a spate of cases of criminals posing as travellers on long-haul flights who target cabin luggage placed in overhead cabin compartments. It said some have even flown business class to target victims.

A source with knowledge of the investigation, told the newspaper: "Initial investigation showed $200,000 and two luxury watches - a Rolex and a Patek Philippe - were stolen from his bang and the total value was about HK$2m."

Saci was believed to have been seated in the economy cabin. He was on his way to Hong Kong for business, the newspaper said.

Local police and airlines have joined forces to fight the increasing number of in-flight thefts, the paper said. It added in the first 10 months of last year, a total of 68 reports of thefts were made on flights into Hong Kong, involving HK$4.83m. In 2014, there were a total of 48 reported cases involving HK$2.61m.

A source told the newspaper that well-dressed criminals usually scout their prey before boarding. They then place their own bags in the same overhead compartments as their victims. "They search through travel bags and luggage in the lockers when the owners were asleep or in the toilet."

The source also noted that such thieves usually take aisle seats towards the rear of the aircraft. The source said that in the past, inflight thefts took place in short-haul flights but of recent, it is now taking place in long-haul flights.

The newspaper said that a Chinese national was arrested last October for stealing $1,000 and HK$3,000 in cash from two bags stowed in the storage locker on a Dragoinair flight. He was flying business class when the alleged crime took place.