The Department of Immigration and Border Protection has finally started to concede facts about the Good Friday shooting attacks at the Manus Island Detention Centre.

"Today the department finally conceded that nine people were injured in the attacks, that multiple firearms were used, and that shots were fired directly into the centre," Greens spokesperson for immigration Senator Nick McKim said.

"The Department has known this for some time, but has refused to correct its own erroneous statements."

Peter Dutton placing unreasonable deadlines on claims for asylum is an attack on some of Australia's most vulnerable people and undermines natural justice and the rule of law, Greens Immigration spokesperson Nick McKim says.

"By setting an arbitrary deadline Mr Dutton is deliberately setting desperate people up to fail," Senator McKim said.

"There is simply not enough time for 7500 people to receive the legal advice they need and submit their applications on time."

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."

The Australian government is preparing to completely wash its hands of the men it has detained for four years on Manus Island.

"After four years of hell overseen by the Australian government, these men have now have to make an impossible choice," Greens Immigration spokesperson Nick McKim said.

"The walls of the detention centre were the only thing between asylum seekers and heavy gunfire last month – now Peter Dutton wants to knock down the walls."

Amnesty International's report on the Manus Island shooting and concessions from PNG police have made clear Peter Dutton's catastrophic failure to keep people safe as well as his disgraceful dishonesty.

"The report and PNG police have made it clear that bullets were fired upon the detention centre, contrary to Dutton's claims," Greens Immigration spokesperson Nick McKim said.

"People in his care are being shot at and he has not lifted a finger to keep them safe. This is an appalling act of neglect."

Exorbitant fees for parental visas are deeply unfair and will entrench disadvantage, Greens Immigration spokesperson Nick McKim says.

"The government has finally acknowledged the problems caused by the massive fees in place for parental solution, but this new class of visa won't go anywhere near fixing it," Senator McKim said.

"A $10,000 visa fee will be a huge burden to migrant families, especially when they will be forced to pay for private health insurance on top of that."

"Those who can't afford to pay such exorbitant costs will be left in the lurch."

Greens Immigration spokesperson Nick McKim says the decision to bar him from visiting Australia's Manus Island detention centre continues the disgraceful secrecy of the Australian government's policies.

"This is a deeply disappointing decision that shows the utter determination to keep a veil of secrecy around Australia’s detention centres and the Good Friday attacks," Senator McKim said.

"People are being warehoused as far from scrutiny as the Australian government can hide them."

"It would not surprise if Peter Dutton has his fingerprints on the decision."

Evidence presented to the Senate inquiry into the conditions on Manus Island and Nauru should prompt the immediate closure of both offshore detention centres, Greens Immigration spokesperson Nick McKim says.

"Australia’s centres on Manus Island and Nauru are inhumane, non-compliant with international obligations, and should immediately be closed and all detainees brought to Australia," Senator McKim said.

Peter Dutton has been caught out lying about people seeking asylum on Manus Island and must resign or be sacked, Greens Immigration spokesperson Nick McKim says.

"Statements from Papua New Guinea police have exposed Mr Dutton’s lies. This has disturbing echoes of the children overboard scandal," Senator McKim said.

"This was an outrageous lie designed to pour scorn on the people he has left stranded on Manus Island."