Monsoon rains have complicated the frantic search for the children, aged 11 to 16, and the coach who have not been heard from since they ventured into the Tham Luang cave last Saturday in northern Thailand and were blocked by heavy rains.

But a break in the wet weather and the establishment of a forward operating base inside the twisting chambers has raised hopes that the 13 could be located and tended to soon.

"Today what we have to do is to rush to the kids," Thai Navy Seal commander and Rear Admiral Apakorn Yookongkaew told reporters at the site. "We will not stop until we find them."

Responders are placing extra oxygen tanks along the walls and lighting in hopes that they can provide a path to an airy chamber called Pattaya Beach where officials believe the team may have taken shelter.

The base will also help rescuers bring the boys out if and when they are found, and provide them with immediate food and medical assistance.

"We have a plan today for the next process after the rescue. We have a plan about what to do, how the treatment will be," Chiang Rai governor Narongsak Osottanakorne said, adding that they were also exploring entering the cave by drilling from above.

The upbeat attitude comes after a week of heavy rains that pounded the area near the Myanmar and Laos borders, making it difficult to reach deeper into the 10-kilometre-long (six-mile) recesses of Tham Luang.

"I'm feeling happy like I've never felt in a long time. Many good signs," the football team's head coach Nopparat Khanthavong, 37, told AFP on Sunday.

"The rain has stopped and rescue teams have found potential ways to reroute the waterway," diverting its flow so no more enters the cave, he said. "The families are feeling much better too."

- 'I miss them' -

The dramatic wait has transfixed Thailand, dominating front pages of newspapers and grabbing international headlines.

Teams of foreign experts from Australia, England, Japan and China, including more than 30 US military personnel, have descended on the remote mountainous site to join some 1,000 Thai rescuers.

Outside the main entrance other searchers were trying to find a way into the cave through separate chimneys, and rescue personnel conducted mock operations in case they should find the boys and need to rush them to hospital.

Large water pumps were also installed in a nearby village to drain water from the area.

Tham Luang is one one of Thailand's longest and toughest caves to navigate, but drilling experts hope its limestone formations could mean a series of holes and alternative entrances that could possibly be explored by camera.

"We still expect some difficulties, because we have to drill not vertical, but inclined," Suthisak Soralump, a geotechnical engineer leading up drilling efforts, told AFP. "But anyway we put our best team in Thailand to come. So let us try."

Officials said the boys know the site well and have visited many times before, so they may have been able to take refuge above the floodwaters.

Rescuers found footprints and handprints in a chamber earlier in the week, farther in from where they had found the kids' football boots, backpacks and bicycles.

Relatives and friends have held vigils and prayed for their safe return.

"I miss them," said 15-year-old Thananchai Saengtan, a friend of a player. "I want them to come back so we can play football together again."