Air Niugini has indefinitely suspended all its flights to Wewak in East Sepik Province.
In a statement, the airline says the move is due to the current security uncertainties and follows instructions from the Acting Minister for State Enterprises.
Wewak is the home town of Sir Michael Somare who maintains that he is the legitimate prime minister.
The airline has also suspended operations to Lae-Morobe, Vanimo-Sandaun and Kiunga in the Western Province for today.
The destinations all have military bases.
Air Niugini says the situation is beyond the airline's control.