Bangkok, Jun 29 (IANS): Rescuers looking for 12 teenage football players and their coach have discovered a hidden opening deep in the jungle that may be a new point of entry to the cave system in northern Thailand that the group is suspected to be stranded in.

On Friday, trekkers discovered the potential access point in the Pha Mee hills above the Tham Luang Nang Non cave system and are now exploring the possibility it connects with the caves below, in which the group is thought to have been trapped for almost a week, CNN reported on Friday.

The natural chimney, which is around 1.5 metres in diameter and at least 22 metres deep, was found to the north of the opening of the cave, where the boys' bikes were found June 23.

Approaching the tunnels from above is "more promising" according to British rescuers at the scene, as it bypasses a passage blocked by floodwaters.

Two British cave experts entered the chimney , managing to descend to a depth of about 20 metres.

Though this is not the first natural chimney found on Pha Mee, it remains the most promising, according to search and rescue teams on site, reports CNN.

Heat imaging drones are also being used to search the hilly terrain above the cave system.

Earlier, trekking teams had found a vertical shaft that appeared to lead into the cave and dropped in food and drinking water, in case the group was nearby, Thanya Netithamkul, director general of the national park, wildlife and plants department said.

Thai Prime Minister Prayut Chan-o-cha visited the rescue site Friday, meeting with officials and the families of the boys.