BANGKOK, Sep 20 (AFP) - The Thai king's son has called for open discussion of the country's tough laws against insulting the royal family, a sensitive topic that has seen hundreds of people prosecuted in recent years.

Vacharaesorn Vivacharawongse, the second son of King Maha Vajiralongkorn, made the comments after visiting an exhibition in New York highlighting people prosecuted under the strict Thai royal defamation legislation.

The law - often referred to as 112 after the relevant section of the criminal code - shields the king and his close family from almost all criticism and can carry heavy jail sentences.

"I attended as a Thai national who loves and respects the monarchy but I believe that 'knowing' is better than 'not knowing'," Vacharaesorn posted in Thai on Facebook.

"Everyone should share their opinions based on different experiences."

He wrote that ignoring opinions does not make them disappear.

"Because of that, I believe that listening to them is a good thing," the 42-year-old wrote.

Critics have long maintained the laws have been weaponised to silence dissent.

Huge protests in 2020 saw thousands urging reform of the laws, a call championed by the progressive Move Forward Party (MFP) that won the most seats in a national election in May.

MFP's determination to revamp the laws eventually saw it blocked from taking power by conservative pro-royalist forces in parliament.

The "Faces of Victims of 112" show at Columbia University was organised by exiled Thai royal academic Pavin Chachavalpongpun, who confirmed to AFP that Vacharaesorn had attended as a guest.

"He is interested in the issue and he said that, despite differences of opinion on this issue, there should be a way that we must communicate," he said from New York.

Vacharaesorn made an unexpected visit to Thailand in August - his first in nearly two decades - having spent most of his life abroad following his parents' separation.

His visit came at a sensitive time for the Thai royal family, with the king's eldest daughter Princess Bajrakitiyabha Mahidol still in hospital after collapsing and losing consciousness in December.

The palace did not comment on the visit.

The king, who has seven children from four marriages, has not formally named an heir, although Thai succession rules favour sons.