Air Niugini's planning manager says the shortage of fuel has affected its domestic flights out of Port Moresby, since Sunday.
David Glover says as far as he knows there has never been a shortage of fuel for airplanes in the capital.
He says he believes Shell's fuel shortage was due to fuel that became contaminated and could not be used.
Mr Glover is optimistic that flights will resume before the busy Easter period.
"Its very costly, and at the moment our priority is to try to operate as best we can and look after as many passengers as we can but obviously after the event we will be adding up exactly what it has cost us, obviously losing up to half of the domestic flights everyday."
David Glover says however Qantas code share flights to Australia have been unaffected by the fuel shortage.