Figures showing 428 children remain detained demonstrate the Immigration Minister continues to flout our international obligations and neglects his duty as legal guardian to act in their best interests, the Australian Greens said today.

"Australia is still punishing, rather than protecting, vulnerable children by locking them up simply because they have fled war, torture and persecution," Greens' immigration spokesperson, Sen. Sarah Hanson-Young, said.

Federal government figures out today showing more than a quarter of a million families are now receiving their child care rebates fortnightly is proof the scheme negotiated by the Greens is working.

"It's great news that 270,000 families are now getting their rebates paid fortnightly instead of monthly," Greens' early childhood education and care spokesperson, Sen. Sarah Hanson-Young, said today.

"Early last year the Greens convinced the government to make the rebate payments fortnightly.

The Greens' moves for an inquiry into the jailing of Indonesian children alongside Australian adults has been supported by revelations today the Australian Human Rights Commission has asked for an independent review into 17 similar cases.

"We've long held concerns about why Indonesian children have been prosecuted and convicted based on wrist x-rays to determine their age, and these concerns have been supported by the Commission's own inquiry," Greens' immigration spokesperson, Sen. Sarah Hanson-Young, said.

The Australian Greens have announced that when parliament resumes in May they will move for an inquiry into the case of an Indonesian boy who has been jailed alongside adults in a maximum security prison in Western Australia.

"We need to learn why Ali Jasmin was put in an adult jail despite documentation showing he was a child and how many other young people are in the same position," Greens' immigration and youth affairs spokesperson, Sen. Sarah Hanson-Young, said today.

The Australian Greens have today written to the Attorney-General and Home Affairs Minister urging they immediately examine the case of an Indonesian boy who has been jailed alongside adults in Western Australia and audit prisons to find similar cases.

"This injustice must be remedied because Australian authorities had Ali Jasmin's birth certificate all along but it was never given to a court when determining his age," Greens' immigration and youth affairs spokesperson, Sen. Sarah Hanson-Young, said today.

Revelations by The Project that Australian authorities had the birth certificate of an Indonesian boy but ignored it before he was later jailed alongside dangerous adult offenders shows why there must be an audit into similar cases, the Greens said today.

"I'm appalled that this vital document was not given any consideration in determining his age or presented to a court after he was charged with people smuggling," Greens' immigration and youth affairs spokesperson, Sen. Sarah Hanson-Young, said.

The Australian Greens have today widened the public discussion about nannies by announcing they will move in Parliament to have the Productivity Commission review all funding of childcare services.

"There's been a lot of debate lately about whether the childcare rebate should be extended to fund in-home care, but that's not the silver bullet for all families," Greens' early childhood education & care spokesperson, Sen. Sarah Hanson-Young, said.

The Australian Greens have today called on the Opposition to support a long overdue review by the Productivity Commission into how the government funds early childhood education and care services.

"We have for some time been calling on the government to direct the Productivity Commission to review how the childcare rebate and childcare benefits are used to fund services," Greens' early childhood education & care spokesperson, Sen. Sarah Hanson-Young, said.

A Senate inquiry has today heard Australia keeps detaining Indonesian children contrary to international obligations, with one imprisoned for 735 days before being released after authorities conceded they were a child.

"I'm outraged some Indonesian children have languished in Australian detention centres and prisons for at least a year because authorities didn't believe they were children, and didn't go to Indonesia to find out," Greens' immigration spokesperson, Sarah Hanson-Young, said.

The Australian Greens have called on the government to make children's rights a priority and sign a new UN treaty on children and young people which has yet to take effect because of an insufficient number of signatories.

"Australia has no excuse for not signing the Third Optional Protocol to the Convention on the Rights of the Child which opened for signatures in late February," Greens' human rights spokesperson, Sen. Sarah Hanson-Young, said today.