Air Niugini flight attendants in Papua New Guinea plan to walk off their jobs to back demands for better working conditions.
They are also seeking the reinstatement of two of their colleagues, who were allegedly sacked.
The National newspaper says action will be taken on Wednesday, while the flight attendants' association says this will happen on Friday.
Its general secretary, Milan Dirua, announced the plans after the National Court refused to agree with the airline management's interpretation of heavy crewing.
The airline had gone to court seeking clarification on whether heavy crewing meant crews could work a maximum of 16 hours, as set down by the Civil Aviation's Authority Act.
The union says members are only required to work a maximum of 14 hours and any more is a breach of CAA rules.