Rescue teams are set to drill into a cave system in Thailand in the hope of freeing a group of young footballers who have been trapped by flooding waters for almost a week.

The Independent reports US army troops and a number of British divers have joined elite Thai Navy SEALS in the delicate search operation. More than 600 rescue workers have been involved in the search.

The 12 footballers - aged between 11 and 16 – and their 25-year-old coach haven’t been heard from since entering the Tham Luang cave tunnel on Saturday. They are all members of the Moo Paa Academy football club.

However, earlier this week Navy divers said they found fresh footprints inside the cave system, with speculation the group might have moved to higher ground.

Muddy water rising to the ceiling of one of the chambers has prevented Thai navy SEAL divers from progressing farther into the cave. Rescue teams have also been forced to turn off industrial pumps being used to drain water over electrocution fears.

“We will drill down from one of the chimneys,“ the Independent quotes Thai army commander Buncha Duriyapan as saying.

Officials have been bringing in large water hoses and water pumps to deal with the flooding while navy divers work their way through the cave's passages.

Rescue authorities have also said that water levels were rising in some places at a rate of 15cm per hour.

"We tried to pump the water (out of the chamber) but the water keeps rising. That means the water that comes in with the rain is still much more than what we can pump out," said Chiang Rai Governor Narongsak Osatanakorn.

"So we need to pump the water faster."

The cave complex extends several kilometres and has wide chambers and narrow passageways with rocky outcrops and changes in elevation.