Korean Air said on Wednesday it would let its crew use stun guns more aggressively and put more male staff aboard flights to clamp down on violence, after an incident involving an unruly passenger.

South Korea's flag carrier said it was tightening security after 1980s US pop singer Richard Marx lashed out at the company on social media for its handling of the incident.

Until now, the use of stun guns or tasers has been limited to situations where there was an "imminent threat to the lives of passengers and crew or to safe navigation", said airline spokesman Nathan Cho.