Immigration Department officials have told the Senate that 158 unaccompanied minors are in detention centres around the country, giving the government another 158 reasons why such these children need an independent advocate, the Greens said today.

"These 158 children have sought Australia's protection but none are having their voices heard independently, because of the Immigration Minister's conflict of interest," Greens' spokesperson for immigration & young people, Sen. Sarah Hanson-Young, said.

The Australian Greens say it is a positive step that three Indonesian children detained in Australian adult prisons have been confirmed as minors and are now going home, but their incarceration should never have happened.

"We welcome the Attorney-General's decision to free three Indonesians but they shouldn't have been convicted and jailed with potentially dangerous adult offenders," Greens' immigration and youth affairs spokesperson, Sen. Sarah Hanson-Young, said.

The Australian Greens have today urged the federal government to change the ASIO Act after revelations another family has been torn apart and faces indefinite detention even though they have been granted refugee protection.

"The Greens were deeply upset by last night's Lateline story on a young Sri Lankan woman and her two sons who have been removed from Melbourne to Villawood detention centre," Greens' immigration spokesperson, Sen. Sarah Hanson-Young, said.

The Australian Greens today announce they've successfully created a parliamentary inquiry to examine whether Indonesian children are being held in facilities such as prisons and remand centres where adults are also kept.

"There are at least two dozen Indonesians who may be children who have been convicted and jailed alongside Australian adult offenders," Greens' immigration and youth affairs spokesperson, Sen. Sarah Hanson-Young, said.

The Gillard government's 2012 budget will fund the biggest migration programme since 1945, but fails to give a fair go to some of the world's most vulnerable people, the Australian Greens said today.

"Although Australia now has its largest permanent migration intake since World War Two, the government has overlooked Australia's humanitarian and family reunion places," Greens' Immigration & Citizenship spokesperson, Sen. Sarah Hanson-Young, said.

The blow out of more than $1 billion dollars in the Immigration Department's budget was avoidable had the government finally put time limits on detention and increased community release places, the Australian Greens said today.

"The annual average cost of a community release programme is $10,400 per person, compared to more than $137,000 if an asylum seeker is kept indefinitely in a detention centre," Greens' immigration spokesperson, Sen. Sarah Hanson-Young, said.

The government can trim the Immigration Department's budget from blowing out in the vicinity of $3 billion this Tuesday by putting time limits on detention and funding more community release places for asylum seekers, the Australian Greens say.

"It's 90 percent cheaper and 100 percent fairer for asylum seekers to live in the community once health and security checks prove it's safe than warehousing them in detention centres," Greens' immigration spokesperson, Sarah Hanson-Young, said today.

The Australian Greens have today urged the Immigration Minister to relinquish his role as the legal guardian of 26 Vietnamese unaccompanied children in detention in Darwin and release them into the community.

"The Minister must cease being the legal guardian of all unaccompanied children and be replaced by an independent advocate who can act in their best interests and stand up for their welfare," Greens' immigration spokesperson, Sen. Sarah Hanson-Young, said.

A Senate committee has today determined action is required but failed to support two Greens' bills that would stop Indonesian children being imprisoned as adults and poor fisher men being used as scapegoats for people smuggling kingpins.

"The bills seek to correct injustices in the system that have led to little fish being caught by Australian authorities while people smuggling syndicate heads continue to get away," Greens' immigration spokesperson, Sen. Sarah Hanson-Young, said.

The report delivered today by the Joint Select Committee on the Immigration Detention Network contains critical recommendations that the government must urgently implement in full.

"The recommendations provide a blue print for a humane, practical and cost-effective response to asylum seekers," Greens' immigration spokesperson, Sen. Sarah Hanson-Young, said.