A researcher says Australia's decision to excise the mainland from the migration zone as a way to force asylum seekers to its offshore detention centres in Nauru and PNG's Manus Island is retrograde.
Professor Sharon Pickering, a criminology researcher at Monash University in Victoria, says the policy harms Australia's international reputation.
The bill was passed last week with support of the opposition coalition.
The Greens Party argued in favour of opening the centres for inspection by Australia's Human Rights Commissioner and giving media access to the centres, but this was rejected.
Professor Pickering says under international law Australia is accountable for what occurs at the centres.
"This is a most retrograde policy for Australia, to restrict the kind of usual checks and balances, the kind of watchdog eye, this is unacceptable."
Professor Pickering says ultimately many of these asylum seekers will arrive onshore, and they should be treated humanely from the start.