A Thai woman accused of insulting the country's late king was forced to kneel before his portrait outside a police station on the island of Samui as several hundred people bayed for an apology.

The woman's arrest and public shaming on Sunday was the latest of several such incidents since King Bhumibol Adulyadej died last week, plunging Thailand into mourning.

Authorities are also urging calm as social media throbs with criticism of people who aren't wearing black and white clothing to mourn the revered monarch. A government spokesman said some Thais can't afford mourning clothes and urged tolerance.

There have been reports of price gouging as demand for such clothing has surged.

Foreign governments have warned citizens in Thailand to avoid behavior that could be interpreted as disrespectful.