Settlement in the Manus Island class action is an admission by Peter Dutton that he is responsible for the illegal detention and deliberate harm of people seeking asylum in Australia, Greens Immigration spokesperson Nick McKim says.

"These 1900 men who sought safety in Australia have lost their freedoms, their families and their futures because of Peter Dutton's decisions," Senator McKim said.

"No amount of money can compensate for this."

Documents showing a plan to make conditions worse for people in Australia's Manus Island detention centre are proof that the torture of innocent people seeking asylum is Australian government policy.

"Punishing people and subjecting them to degradation to coerce an outcome fits squarely within the definition of torture," Greens Immigration spokesperson Nick McKim said.

"The Australian government, and the private contractors it has employed, are in clear breach of their legal and moral obligations."