Thailand Wednesday granted citizenship to stateless members of the football team rescued from a cave last month in a saga which gripped the world.

The story of the "Wild Boars" club has dominated headlines since the 12 boys and their 25-year-old coach went exploring in Tham Luang cave on June 23 and were trapped deep inside by rising floodwaters, setting off an international search dubbed "Mission Impossible".

They spent nine days inside subsisting on rainwater from rocks before being located. Days later they were extracted in a complex operation in which they were sedated, carried and stretchered out of the waterlogged passages.

Thailand is home to around 480,000 stateless people, according to the UN refugee agency. The long-ignored issue came into focus during the rescue mission when it was revealed that four of those trapped inside lacked citizenship, prompting calls for the government to fast-track applications.

"Today all of you get Thai citizenship," Mae Sai district chief Somsak Khanakham said in a ceremony on Wednesday at a local office, as they were handed national ID cards.

Somsak told AFP that the "Wild Boars incident" had nothing to do with the development and said they had merely qualified.

But the event was advertised proudly on the local government's Facebook page with the words: "Wild Boars revel! Got Thai citizenship."

Many of Thailand's stateless people are from nomadic hill tribes and other ethnic groups who have for centuries lived around the borders of Thailand, Myanmar, Laos and China.

The family of one of the four footballers granted papers, Adul Som-on, is from Myanmar's Wa State, a self-governing region.

Weeks after the rescue, interest in their ordeal is still strong and Hollywood-style production houses are racing to take the story to the big screen.

But authorities have asked media to keep their distance while the teammates readjust to normal life, and avoid touching off lingering trauma.

The dangerous rescue brought all 13 members of the team to safety. But a former Thai Navy Seal diver died while installing oxygen tanks in preparation for the extraction.

Eleven of the boys and their coach recently entered a monastery for several days to ordain and "make merit" according to Buddhist ritual for Saman Kunan.