While the Law Council has raised concerns over the legislation, Opposition home affairs spokeswoman Kristina Keneally said Labor had been convinced it was necessary in talks with Mr Dutton and Attorney-General Christian Porter.

Senator Keneally said the government, based on Solicitor-General's advice, wanted the amendments in place ahead of the deadline for submissions in the High Court case to be filed on Friday.

"The nature of this legal challenge, if it was successful – and we understand there is a very high likelihood the legal challenge will be successful – would leave the ACIC exposed in terms of its current operations as well as the validity of convictions based on its previous operations and investigations," Senator Keneally said.

Bipartisan position

While there is wariness within Labor over the retrospective nature of the legislation, on balance MPs did not want to give the government an opening to label the Opposition as soft on crime or bikies.

The bipartisan position means the legislation will sail though Parliament but Centre Alliance Senator Rex Patrick will try to move amendments anyway.

"Centre Alliance is examining the bill in detail, but has preliminary concerns about removing safeguards over the very coercive powers that can be invoked for ‘special investigations’. The retrospective provisions in the proposed legislation are also concerning," he said.

Law Council president Arthur Moses said it was disappointing Labor was supporting the government to give the ACIC a blank cheque to exercise its powers at the expense of individuals' rights.

"This is an abrogation of the responsibility of parliamentarians to properly scrutinise radical legislation which purports to validate past unlawful conduct by the ACIC and broadens the scope of its coercive powers without understanding the consequences," he said.

"It is troubling that even in the wake of media raids this year that highlighted defective laws that the Parliament is being asked to wave through flawed legislation without waiting for the High Court to determine the matter which has been granted special leave."