The Commission's President Gillian Triggs says there are two key parts to the inquiry.
"Carers, professionals, medical professions, nurses, all the people that have come into contact with this policy of detaining children we'd like to hear from," she says. "The other element to the inquiry is that I will with two members of the commission staff be going to all of the detention centres in which children are held, with the single exception of Nauru, where I do not have jurisdiction."
(Click on the audio tab above to hear the SBS Radio story)
The federal government is in negotiations with a construction company to take over welfare services from the Salvation Army for asylum seekers in detention on Nauru and Manus Island.
Transfield Services announced it will be responsible for support and welfare services on Nauru and Papua New Guinea's Manus Island, in a statement to the ASX last week.
The coalition government cut the Salvos loose last year and their $74 million contract expired on January 31.
The charity provided educational and recreational activities such as English classes, gym and computer access for asylum seekers.
Transfield Services spokesman David Jamieson said the company would retain 40 per cent of the Salvo's 300 subcontracted staff working under the previous contract.
"It's absolutely not a case of us walking in wholesale and starting from scratch," he told AAP, adding that the company provides entertainment and recreation programs at defence bases in Australia.
Mr Jamieson clarified that the more specialised counselling would still be handled by medical personnel working for Integrated Health Management Services.
Transfield Services is still in negotiations with the Department of Immigration and an overall figure for the contract has not been finalised.
The new contract will start this month, Mr Jamieson said.
Transfield is an Australian-based global national corporation that provides operations, maintenance and construction services.
It operates in 11 countries across 18 industries including defence and mining.
Prime Minister Tony Abbott's commission of audit head Tony Shepherd stepped down as chairman of Transfield Services in October.
Transfield will also be taking over "garrison services" such as building maintenance, catering and security.
G4S, a private security firm, did not have its $80.5 million government contract to manage the Manus Island detention centre renewed late last year.
Transfield already has millions of dollars of contracts mostly with the Department of Defence for building, construction and repair services.
Immigration Minister Scott Morrison said the government is reorganising its contractual arrangements to ensure a more integrated operation and more details will be released in due course.
Refugee Action Coalition spokesman Ian Rintoul said Transfield's top priority would be its shareholders rather than the welfare of asylum seekers.
"They (the government) wanted to remove the Salvos because they actually had the interests of asylum seekers at heart," he said.
"Transfield is only interested in the bottom line."
Mr Morrison said the government would co-operate with the inquiry and consider its recommendations.
"But the reason there are children in detention is because over 50,000 turned up on illegal boats on Labor's watch so we're dealing with Labor's chaotic mess here," he told Macquarie Radio.
Mr Morrison said there were more than 1000 children in detention when Labor lost office.
The Commission is due to report on its findings by the end of the year.
