Retrospective laws will be pushed through NSW parliament within days to enshrine corruption findings already handed down by the state's ICAC.
But NSW Premier Mike Baird has stopped short of giving the corruption watchdog more power for future investigations.
Instead he has appointed a retired High Court judge to review the watchdog and make recommendations to strengthen its powers - or rein them in.
"We will not tolerate corruption in this state, end of story," Mr Baird said.
He promised new laws, backed by Labor, to ensure existing corruption findings stick, despite a damaging High Court ruling last month that confirmed the ICAC had over-reached when it launched a probe into high-ranking Crown prosecutor Margaret Cunneen SC.
That decision prompted the ICAC to announce it would consent to orders sought by mining magnate Travers Duncan, John McGuigan, Richard Poole and John Atkinson to have corrupt conduct findings made against them declared invalid.
"All previous findings of corruption by ICAC should, and will, stand - and we will introduce a bill to that effect immediately," Mr Baird said.
"While the High Court's recent decision raises important questions about the ICAC's jurisdiction for the future, it should not provide those who have done the wrong thing in the past with a loophole."
One of the men whose appeal against the corruption tag spurred the premier to act, Mr McGuigan, described the government's plans as "totally at odds" with the principal of separated powers.
"For the NSW government to pass retrospective legislation purporting to make legal that which is illegal makes a mockery of the judicial process," he said in a statement.
"The High Court in Cunneen did not reveal a `loophole' but rather determined the proper scope and extent of ICAC's powers."
Mr Baird has announced a wholesale review of the ICAC, to be led by "the greatest legal mind in the country" - former High Court chief justice Murray Gleeson QC.
He is due to report back to parliament by July, and further legislative tweaks may be made in line with his recommendations.
Mr Baird expects the first set of reforms to go before parliament by next week.
Opposition Leader Luke Foley has pledged his support.
"I am delighted that former Labor MPs and their cronies who were found by the ICAC to do the wrong thing won't be able to wriggle their way out of it," he said.
Legal experts had warned the Cunneen ruling would have a knock-on effect for corruption findings previously made by the ICAC, and for inquiries close to being finalised.
Operations Credo and Spicer, which probed allegations involving Australian Water Holdings and former Liberal ministers including Chris Hartcher and Mike Gallacher, were also thrown into doubt.
The ICAC announced last year it would hold off on delivering reports into those public inquiries.
The watchdog is expected to wait until the results of the Gleeson review, and any new legislation, before handing down its findings.
