Singapore Airlines (SIA) flights to Bangkok will operate as scheduled despite the Thai army imposing martial law in the country.

But SIA will waive administrative fees and penalties for refunds, re-booking or re-routing for passengers who decide to change their travel plans. These passengers must hold confirmed tickets issued on or before May 19 for travel to and from Bangkok, on or before May 31. This also applies to redemption tickets.

The airline operates 35 weekly services to Bangkok.

"Our Bangkok flights are currently operating as scheduled," said an SIA spokesman. "We will be monitoring the situation and will provide updates on our website whenever necessary."

The airline advises passengers who are going ahead with their trips to make arrangements to head to the Bangkok airport at least four hours prior to departure, and use the airport rail link. Traffic jams may be expected in the city due to road closures.