Singapore police and courts will get wider powers to deal with troublemakers on flights when new laws are passed in the next six to 12 months.

The move will come before a global ruling by the United Nations aimed at tackling the growing problem of unruly air passengers, The Straits Times has learnt.

Under current international civil aviation laws stipulated by the Tokyo Convention, Singapore can take action only if the culprit arrives on Singapore Airlines (SIA) or other Singapore carriers.

This means that troublemakers on foreign carriers usually get off scot-free. To plug this loophole, the International Civil Aviation Organisation (ICAO) - the UN's civil aviation arm - aims to replace the Tokyo Convention with the Montreal Protocol.

The new protocol, expected to come into force within two to three years, will give countries more teeth to deal with offences such as travellers refusing to comply with safety instructions and physically or verbally abusing cabin crew.

Singapore, which plans to enact its own laws before the global mandate, has consulted airlines operating at Changi Airport.

All support the initiative, according to a spokesman for the Civil Aviation Authority of Singapore. "The ability to take such law enforcement action would be a strong deterrence against unruly behaviour on board aircraft arriving in Singapore," she said. "This would enhance Singapore's status as a safe and secure air hub."

Mr Tim Colehan, assistant director for member and external relations at the International Air Transport Association (Iata), which represents global carriers, said there has been a rise in unruly behaviour on aircraft in recent years.

In 2014, airlines reported 9,316 incidents of such behaviour, or one for every 1,400 flights. From 2007 to 2014, the average was one per 1,530 flights.

In a survey by Iata, four out of 10 airlines said they have had to divert a flight in the last 12 months because of troublemakers.

Urging the ICAO and countries to move quickly to introduce tougher laws globally, Mr Colehan said that, in the meantime, airlines, ground handlers and even airport restaurants and bars can do their part.

For example, there are instances when bad behaviour is detected at check-in or during screening, and this is where ground handlers and security personnel can alert the airline, so it can make an informed decision on whether or not to accept the passenger for boarding.

SIA spokesman Nicholas Ionides said crew are trained to deal with potential cases of passengers who exhibit unruly behaviour.

"Some of these methods include politely declining drinks if the crew discerns that the passenger has had too much to drink," he said. "In extreme cases where passengers turn violent, our crew are also trained in appropriate ways to handle them."

Ground staff may also refuse boarding to passengers who have already displayed errant behaviour on the ground, in order to not compromise the safety and comfort of other travellers, he added.

Singapore Airlines Staff Union president and steward Alan Tan said: "The aim is always to defuse the situation but this is not always possible, so we do sometimes have to hand passengers to the local police after landing.

"But because of a lack of jurisdiction, police may not always be able to act except to issue a warning. This can be quite frustrating."