In an update on its website, SIA said the extended cancellations were due to the "geopolitical situation" in the Middle East, warning that other flights could also be affected as conditions remain "fluid," Channel News Asia reported.
Singapore Airlines and Scoot have suspended flights to the Middle East since Feb. 28 when the U.S. and Israel launched strikes on Iran, triggering wider regional instability.
Passengers impacted by the cancellations will be rebooked on alternative flights or may request a full refund for the unused portion of their tickets.
Those who booked directly with the airline can apply online, while customers who purchased tickets through travel agents or partner carriers are advised to contact them directly.
The ongoing conflict has led to tens of thousands of flight cancellations worldwide.
Airlines have also been forced to reroute services to avoid Iranian and nearby airspace, resulting in longer flight times, higher fuel consumption and increased operating costs.