Australia is now known around the world as the most inhumane, the most uncaring and the most selfish of all the wealthy countries, former prime minister Malcolm Fraser has declared.

Mr Fraser says migration legislation passed last week has given Immigration Minister Scott Morrison "dictatorial, tyrannical powers" over the lives of asylum seekers and "destroyed the rule of law as we know it".

Immigration Minister Scott Morrison. Credit:Alex Ellinghausen

He has accused the crossbench senators who supported the legislation, on the basis of concessions they negotiated with Mr Morrison, of committing "a political error of fundamental proportions".

Speaking at the opening of the Asylum Seekers Resource Centre's new premises in Footscray, Mr Fraser said the children Mr Morrison had agreed to release from detention could be sent to their home countries under new 'fast track' processing, or face years in limbo on temporary visas that preclude family reunion.