Divers will resume the mission to rescue eight members of a boys' soccer team and their coach from a flooded cave in Thailand today, after the first phase of the operation saw four boys reach safety yesterday.

Key points: Four boys taken to hospital after being rescued from the cave

Four boys taken to hospital after being rescued from the cave 90 divers involved in rescue, according to the head of the operation

90 divers involved in rescue, according to the head of the operation Mission put on hold for "about 10 hours" as rescuers prepare for the next phase

The rescued boys are reported to be in good condition but remain in hospital under observation.

Thailand's Interior Minister Anupong Paojinda said officials were meeting this morning about the next stage of the operation and how to extract the remaining nine people from the cave in the country's north.

He said the divers who successfully rescued four boys yesterday would be tasked with getting the rest of the trapped people out.

But first, Mr Anupong said divers needed to place more air canisters along the underwater route, a process expected to take several hours.

Nineteen Australian personnel are involved in the rescue operation, including a doctor who has played an essential part in assessing which boys can leave and in what order.

Foreign Minister Julie Bishop told reporters that anaesthetist and experienced cave diver Richard Harris is working with the Thai medical team inside the cave "to make the decisions about the order in which the boys were to be extracted".

A police helicopter is met by an ambulance after some of the boys were taken from the cave. ( Reuters: Athit Perawongmetha )

The first four boys removed from the cave yesterday were taken straight to hospital, according to the head of the rescue operation, Narongsak Osottanakorn.

"The operation went much better than expected," Mr Osottanakorn said.

"I would like to inform the public at home and those who have been giving us support all along, after 16 days, today's the day we've been waiting for, we are seeing the Wild Boars in the flesh now," Mr Osottanakorn added after the first boys emerged.

The Wild Boars is the name of the football team.

Sorry, this video has expired Four members of Thai soccer team rescued

Ninety divers, including 50 foreign rescue workers, have been taking part in the operation, with the first boy leaving the cave at 5:40pm (8:40pm AEST) on Sunday.

Mr Osottanakorn said rescue workers needed between 10 and 20 hours to prepare for the next operation at the site.

Sorry, this video has expired Thai rescue chief confirms that some of the 'Wild Boars' have been rescued

After the successful first phase of the rescue, Thai Navy SEALs, who are taking part in the operation, posted on their Facebook page: "Have sweet dreams everyone. Good night. Hooyah."

Loading

Divers had earlier launched a daring and dangerous mission to rescue the children and their coach, who had been trapped underground for more than two weeks.

A military helicopter believed to be carrying rescued boys takes off near the cave. ( Reuters: Soe Zeya Tun )

The only way to bring the boys and their coach out of the cave is by navigating dark and tight passageways filled with muddy water and strong currents, as well as oxygen-depleted air.

A former Thai Navy SEAL passed out and died making the dive on Friday.

Experienced cave rescue experts consider an underwater escape a last resort, especially with people untrained in diving, as the boys are.

The path out is considered especially complicated because of twists and turns in narrow flooded passages.

But Mr Osottanakorn said earlier that mild weather and falling water levels over the past few days had created optimal conditions for an underwater evacuation that won't last if it rains again.

Before announcing that the rescue was underway, authorities ordered the throngs of media that had gathered at the cave from around the world to leave.

'Today is D-Day'

Sorry, this video has expired A 3D model of the cave complex where the boys and their coach are trapped.

The boys' ordeal has drawn huge media attention in Thailand and abroad, and getting the boys out safely could be a boost for Thailand's ruling junta ahead of a general election next year.

"Today is D-Day," Mr Osottanakorn had earlier said.

Bursts of heavy monsoon rain soaked the Tham Luang Cave area in northern Chiang Rai province yesterday and storms were expected in the coming weeks, increasing the risks in what has been called a "war with water and time" to save the team.

The boys, aged between 11 and 16, went missing with their 25-year-old coach after soccer practice on June 23, setting out on an adventure to explore the cave complex near the border with Myanmar and celebrate a boy's birthday.

Rescuing them all could take three to four days and depended on the weather, an army commander involved in the mission said.

Sorry, this video has expired Thai boys in high spirits as rescuers plan next move.

Slow going for rescuers in precarious conditions

The rescue process has been slow and delicate, with each operation taking almost eight hours to execute after many more hours of preparation.

Cave diving expert Professor Peter Rogers told the ABC the conditions rescuers will face mean extreme caution must be taken each step of the way.

Sorry, this video has expired Cave diving expert says he's confident all the boys will be rescued safely

"It's about four kilometres but it is difficult terrain. You're walking along a passageway that's half filled with water for a lot of it," Professor Rogers said.

"The floor isn't flat — it's bits of rock that normally if it was dry, you'd be hopping from one bit [to another] and stepping across.

"But when it is full of muddy water, you slip over, you fall, your feet drop into a hole and you trip. It's really slow."

Sorry, this video has expired Caver and engineer Ron Allum delves into the complexities of the rescue mission

ABC/wires