An Air New Zealand spokeswoman said it was "extremely uncommon" to receive complaints of physical harassment, including sexual harassment, on their flights.
"Our staff are trained in how to manage these situations and the appropriate authorities are informed if we receive a complaint from a customer."
A Jetstar spokesperson said it had a "zero tolerance" for any disruptive or anti-social behaviour.
"Complaints about inappropriate behaviour on our flights are extremely rare, but if a customer is uncomfortable with another traveller's behaviour they should immediately report it to one of our crew who are trained to act quickly if a problem arises on board."
Once the matter is reported the crew would separate those involved, seating them at different ends of the aircraft.
"The operating captain will consider the most appropriate options based on the circumstances, including returning to the departing airport, diverting to the nearest airport or continuing to the destination."
Aviation industry commentator Irene King said there was protocol in place to deal with troublesome passengers dubbed 'unruly passenger offences'.
However, the Civil Aviation Authority (CAA) said the Act didn't cover sexual offences which were automatically referred to police.
King said the airlines should have their own internal procedures under their operational specifications.
"There's a way of alerting the flight attendants and the flight attendant will remove that person to a place of safety and then they will deal with the passenger concerned and that can include up to including physical restraint.," King said.
"They are very, very proactive because obviously any of these threats are deemed to be a threat to flight safety ... I'm surprised that some of these airlines appear to not be as proactive as the legislation in New Zealand requires them to be.
New Zealand jurisdiction covered inbound flights, she said.
"Their operation specifications should cover various foreign jurisdictions and they could differ, but I would be surprised."
However, given the time police needed to investigate it was common for the offending passenger to fly out of the country before being charged.
"They'll be interviewed and assessed, a decision will be made whether to charge them or not, but it's not immediate ... so the passenger may well be in New Zealand and may depart before the matter is dealt with and that too causes problems."
Complaints of a sexual nature were "miniscule", she said, and could recall only one or two cases during her eight years in the industry.
"Passengers consuming alcohol or smoking in the toilets was a much higher incident rate than assault, like sexual assault. There was certainly assaults from consuming alcohol and consuming drugs."
David Kirby, manager of police adult sexual assault and child exploitation, said if people were concerned for their safety on a flight they should report it to the flight crew, who would contact police on the ground.
"If a crime is reported on a plane, the alleged offender will be escorted off the plane by police.
"Most of New Zealand's major airports have airport police stationed at them to respond to such incidents. Specialist investigators will then make enquiries."
A Civil Aviation Authority spokesman said any sexual assault complaint was referred to police.
However, it could prosecute passengers deemed as 'unruly' under the Civil Aviation Act.
'Unruly passengers' include those deemed disruptive, endangering the plane's safety, interfering with the aircraft, intoxicated, offensive behaviour or words, smoking or use an electronic device when told not to.
