
"The list of the lese-majesty perpetrators is an old list that we have," Thai Justice Minister Paiboon Koomchaya told local media, adding that he had asked the relevant agencies to track down in which countries the suspects are currently residing.
"This (the move) is not new. We had in the past reached out to foreign ministers on this matter," he added.
Thai authorities also said Tuesday they would crack down on the spreading of false information and rumours on social media, following the passing of His Majesty.
A spokesman for the National Council for Peace and Order, Piyapong Klinpan, told reporters the move was also designed to prevent royalist vigilantes taking matters into their own hands by attacking others for allegedly insulting the late king, following numerous reports of violence.
Thailand's lese-majesty law is among the toughest in the world and perpetrators can face between three and 15 years in prison.
On Monday, a middle-aged woman was slapped in the face and subjected to verbal abuse by her fellow bus passengers who accused her of defaming the late king.
A video clip that went viral online showed her being forced off the bus and then smacked again on the street afterwards.