'Don't worry dad and mum'

The coach of the youth football team that has been trapped in a cave in Thailand for the past two weeks has sent his "apologies" to the parents of the boys in a scrawled note handed to divers.

The "Wild Boar" football team went exploring in the Tham Luang cave network after a football game on June 23 and got trapped kilometres deep inside the cave system as floodwaters caused by heavy rains blocked the entrance.

The 12 children, aged 11 to 16, are accompanied by their coach, Ekkapol Chantawong, 25.

"To all the parents, all the kids are still fine. I promise to take the very best care of the kids," Chantawong said in a note given to a diver on Friday and published on the Thai Navy SEAL Facebook page on Saturday.

"Thank you for all the moral support and I apologise to the parents."

Other touching notes signed by members of the team were directed to their families, many of whom have kept an anxious vigil outside the cave for a fortnight.

"Don't worry dad and mum," said a note from one of the boys who gave his nickname as "Bew". "I have been away for two weeks but will come back and help you sell your stuff." His family are shopkeepers.

"Love to Mum, Dad and my little brother," reads one note from 15-year-old Phiphat Photi - who is better known as "Nick".

“If I get out, please can you bring me some grilled pork and vegetables?"

The boys, however, were already looking ahead and appealed to their schools not to be too hard on them.

"Teachers, please don't give too much homework," they wrote.

The letters provoked a surge of emotion from families, who endured nine long days before their children were found and now face an agonising wait for a dangerous evacuation.

"I am so happy to see his letter, his handwriting. I'm almost crying," Night's mother Supaluk Sompiengjai, told AFP news agency.“It doesn't matter how long I wait, as long as he is safe."