Fiji's Employment Minister has declared a dispute between air traffic controllers and Fiji Airports an unlawful strike.
The company, which manages both of Fiji's international airports in Nadi and Nausori, has faced protests from controllers this week over pay and working conditions.
FBC News reported that 33 controllers took various forms of leave from Monday until Thursday.
The Minister, Parveen Bala, said their demands and coordinated refusal to attend work constitutes a strike, which is an offence under the Employment Relations Act.
He encouraged both parties to continue discussions in good faith.
One local operator told RNZ Pacific on Thursday the strike had stopped all non-commercial flights at the airports.
Fiji's Civil Aviation Authority said it was "aware and closely monitoring the situation to ensure safety is maintained at all times."
"Contingency Procedures that have been developed for such situations have been activated to ensure the safety of the travelling public is not compromised under the current Fiji Airports staffing circumstances," it said in a statement.