"The last couple of hundred metres underwater is very hard to find your way through". For the entire dive at the back of the cave there's zero visibility (due to) mud and clay, ' Mr Harris told the Prime Minister over Skype.
Mr Shorten said the work of all the Australians involved meant he "couldn't be prouder" to be an Australian.
There were 20 Australians involved in the Thai-led rescue effort.
The Adelaide doctor is globally renowned for his cave-diving expertise. He is a member of the Explorers Club of NY and received an Australian award for 'Outstanding Contributions to Cave Exploration.' In 2011, he recovered the body of Agnes Milowka, 29, after she ran out of air in Tank Cave near Mount Gambier in South Australia.
"It's really nice to be back home with my friends and family", Dr Harris said.
Global attention on their fate and the multinational rescue has put the area firmly on the map, with plans for a museum to showcase the rescue.
Dr Harris assessed the health of the boys and their coach, determining who needed to get out of the cave quickest and who could wait longer. To the Cave Divers Association of Australia for handling the flurry of interest in our sport...the management team there has been awesome especially our best mate John Dalla-Zuanna.
They have built a formidable reputation for their daring dives at some of the world's most risky caves, including Cocklebiddy Cave in Western Australia and the Pearse River on New Zealand's South Island. He has an active interest in diving safety and accident investigation'.
They were discovered nine days later by two British divers, perched on a small ledge of dry land about 4 kilometers (2.5 miles) from the cave's entrance.
The boys appear seated on their hospital beds with their mouths and noses covered by white masks while each of their identification numbers appear on the walls above the beds.
The media-shy 53-year-old was hailed for an ingenious medical idea that helped the trapped boys stay calm during the gruelling 1.7km swim to the surface.
He explained local, and British divers who Dr Harris described as "the awesome foursome", had already laid terrific groundwork to ensure the success of the gruelling mission.
"They also thanked him and promised to be good boys", he said.
After their traumatic ordeal deep inside a dark and flooded mountain cave, Thailand's 12 rescued boys and their young football coach will now have to navigate a fresh challenge: Fame.
The Tai Lue are just one of a number of ethnic groups who for generations have moved across regions and borders in the remote hills between China, Myanmar, Laos and Thailand.
"Now, I am very fine", 14-year-old Adul Sam-on said in English, ABC News reported.
Thousands are calling on Harris and Challen to be presented with the Cross of Valour, Australia's highest civilian bravery award.