A New Zealand woman accused of violating the Thai King by making an improper gesture missed a flight to Auckland this week after police admitted her to hospital.

Thitinant Kaewchantranont, 63, was due to leave Thailand on a Thai Airways flight from Bangkok on Tuesday but did not arrive to check in, the Bangkok Post reported.

Her husband, also a New Zealander, did get on board.

Ms Thitinant, who is understood to have a history of mental illness, was admitted to hospital last Friday after allegedly making an improper gesture towards an image of His Majesty the King outside the Constitution Court on the same day, the newspaper reported.


After lodging a complaint, Thai police referred her to Srithanya Hospital "to see if she is genuinely mentally ill".

About 200 people turned outside the airport to protest against her leaving and she would have been prevented from boarding the plane if she had tried to get on, police reportedly said.

It is understood the plane's captain also said he would have refused to pilot the aircraft if Ms Thitinant was on board, saying she would pose a security risk.