The condition of 87-year-old King Bhumibol -- the world's longest serving monarch -- is a hugely controversial topic in Thailand.
The monarchy is shielded by one of the world's toughest lese majeste laws and prosecutions have increased dramatically since the military took over last year in a coup.
"Today's edition of the International New York Times was not printed in Thailand because it includes an article that our locally contracted printer deemed too sensitive to print," the newspaper said in a letter to subscribers in the kingdom.
When contacted by telephone, a woman at Eastern Printing PCL in northern Bangkok confirmed that their company was the sole printer of the New York Times in Thailand but declined to comment on their reasons for refusing to print the paper.
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"It is not convenient to say anything as we are just a printer, please contact the New York Times," she said.
Local and international media have to routinely self-censor when reporting on the monarchy for fear of falling foul of the broadly worded law, which carries up to 15 years in jail for each count of insulting the king, queen, heir or regent.
It also detailed many of the difficulties in writing about the royal family or gauging its popularity in a country where open debate about its role is all but impossible thanks to the lese majeste law.
King Bhumibol is perceived as a near deity by many Thais and is often seen as a unifying force in a deeply polarised country with a turbulent political history.