Yesterday the full bench of the High Court began hearing a challenge to the Malaysian solution.

The Greens hope David Manne and Debbie Mortimer, SC, and their legal team succeeds, not least because we do not want unaccompanied children to be expelled to a country where their rights cannot be guaranteed. It's not yet clear when the court will issue its ruling, but it could permanently derail the Gillard government's plans to export Australia's international obligations to give protection to countries including Malaysia and, possibly, Papua New Guinea.

Audio from Sen. Hanson-Young's door stop on the latest developments with immigration policy and the Malaysia deal.

We politicians are back in Canberra this morning after a five-week winter recess. It sounds like a long break, but federal politicians work seven days a week, so it passed by in a flash. As a mother of a young daughter, I cherish such times as I was able to spend more time with her. Even the Prime Minister had a few days out of the media spotlight, although she stayed in Canberra. Tony Abbott, too, put the hard hat and reflective vest down for 10 days and went overseas with his family.

The Australian Greens say the Murray Darling Basin Authority's second delay in eight days to the draft report means there's less time for the parliament and public to assess its contents.

"Last week we were cautious about the authority meeting its mid-October deadline and unfortunately we've been proven right," Greens' water and Murray Darling basin spokesperson, Sen. Hanson-Young, said today.

"We're disappointed that there's been yet another delay in this long-overdue draft.

Yesterday the High Court extended an injunction to hear a legal challenge to the Malaysian people-swap deal. The full bench of the court in Canberra will now sit on August 22. The Greens maintain that whatever the court's decision later this month, the policy of expelling vulnerable people, especially children, is wrong and should be abandoned. Under the Refugee Convention, Australia has an obligation not to send people to a country where their safety is compromised.

The Australian Greens are concerned by yet another delay in releasing the draft report by the Murray Darling Basin Authority.

"We have been concerned that some states would continue to play games and veto elements of the draft plan they did not like," Greens' water and Murray Darling basin spokesperson, Sen. Hanson-Young, said today.

"It appears that's what's happened with this latest delay.

"Ultimately these obstacles will mean that the river system suffers.

The Greens have welcomed the SA government's environmental water requirements study, which has been peer-reviewed by the Goyder Institute, to demonstrate what is needed to keep the Murray mouth open and ensure a healthy river system.

"We've always maintained that the protections the river needs must be based on scientific evidence," SA Greens senator and spokesperson for water and the Murray Darling Basin, Sarah Hanson-Young, said today.

There are more than 13 billion reasons why the climate package unveiled on Sunday is better at putting a price on pollution than its predecessor.

For starters, there's $10 billion for renewable energy projects. Unlike the Carbon Pollution Reduction Scheme (CPRS) proposed by the former Rudd government, this package lays the basis for science-based climate action.

The old scheme locked in weak targets for 15 years which could not be strengthened. There was no money for investment in renewable energy and next to nothing for energy efficiency measures.

South Australia will benefit from the historic climate action package which finally puts a price on carbon to cut pollution, the Australian Greens said today.

"The Greens went to the 2010 election promising to take action on climate change, and at last we have the results after many months of negotiations," SA Greens Senator, Sarah Hanson-Young, said.

The Australian Greens, the Labor government and the Independent MPs today announced an historic agreement on a climate action package that will put a $23 per tonne price on carbon pollution, as was first proposed by the Greens, support householders and invest billions of dollars in clean, renewable energy.

This package, which the Greens have helped shape, is the first vital step towards tackling the climate crisis and building a cleaner, healthier, more secure Australia for all of us.