Tuesday marks one year since the tragic death of Reza Barati, a refugee in the care of the Australian Government.

"A year on and we still have no answers and a government that refuses to accept any responsibility for the death of a refugee in its care," Greens Leader Christine Milne said.

"People imprisoned on Manus Island continue to suffer but Reza Barati paid the ultimate price for the Coalition's cruel policy encapsulated in the election slogan to 'stop the boats'.

The Australian Greens are pushing for a comprehensive plan to strengthen Australian society and help make all Australians safer at home, announcing legislation to establish an independent national body to build social cohesion and prevent extremism. The Australian Centre for Social Cohesion (ACSC) would be tasked with overseeing the development and implementation of key preventative programs that combat social exclusion and stop young Australians from becoming radicalised.

Greens Leader Christine Milne has called on Australians to stand together against terrorism threats on home soil, saying unity, not war, will deliver lasting peace.

"The best way to keep Australians safe is to bring them together, not blindly follow the US into an unwinnable war in the Middle East," said Senator Milne.

"Are we going to another war in the Middle East because the terror alert has been raised, or the other way around?