The inspector can deal with complaints about the conduct of the ICAC or its officers which concern abuses of power, impropriety, misconduct of any kind, lengthy delays in investigation and maladministration.

This extends to parliamentarians, local councillors, the Governor of New South Wales, public servants, and staff of universities and state-owned corporations.

There are only limited controls on admissible evidence,[1] which may be obtained by compulsion and coercion or other means that would make it inadmissible in a court of law.

[1] While the ICAC cannot impose custodial sentences (other than for procedural matters), it can recommend that criminal charges be considered by the Department of Public Prosecution.

Introducing legislation to establish the ICAC, Greiner told Parliament:[8] In recent years, in New South Wales we have seen: a Minister of the Crown gaoled for bribery; an inquiry into a second, and indeed a third, former Minister for alleged corruption; the former Chief Stipendiary Magistrate gaoled for perverting the course of justice; a former Commissioner of Police in the courts on a criminal charge; the former Deputy Commissioner of Police charged with bribery; a series of investigations and court cases involving judicial figures including a High Court Judge; and a disturbing number of dismissals, retirements and convictions of senior police officers for offences involving corrupt conduct.... No government can maintain its claim to legitimacy while there remains the cloud of suspicion and doubt that has hung over government in New South Wales.The ICAC's first task was to investigate activities of the previous Wran and Unsworth governments.

In 1992, the ICAC ruled that Premier Greiner's offer of a government job to former minister Terry Metherell was an act of "technical" corruption.

Although the charges were later dismissed by the courts, the four independent MPs on whom the premier relied for a majority in the Legislative Assembly indicated that they would no longer support his leadership.

It recommended the implementation of a new lobbying regulatory scheme to provide transparency and to reduce both the risk of corruption and public distrust.

It called Premier Barry O'Farrell as a witness and asked if he recalled being sent a gift of a $2,978 bottle of wine by the CEO of the company.

The Cunneen decision raised questions about whether ICAC exceeded its powers in some earlier and current high-profile corruption investigations.

The future of the ICAC's powers will be considered by a review, which premier Baird had announced on 5 May, to be headed by former High Court chief justice Murray Gleeson and to report by 10 July.

[33] Duncan challenged the 2015 amendment act,[34] claiming that it infringed the separation of powers established in the federal constitution, which as settled in Kable flows through to the NSW courts by cross-vesting.

[35][36] In October 2021, ICAC announced an investigation into whether then-Premier Gladys Berejiklian had breached public trust or encouraged corrupt behaviour during her romantic relationship with MP Daryl Maguire.

[47][48][49][50][51] In 1994, former Premier Neville Wran suggested that the then Government should consider "[ridding] the ICAC legislation of its glaring abuses of civil rights".

In the wake of the findings of corruption against Eddie Obeid and Ian Macdonald, Graham Richardson, a former Labor Senator, opined that the ICAC had caused "collateral damage" to innocent people, citing Eric Roozendaal as an example.

[52] After O'Farrell's resignation, Bruce Baird, a former State Deputy Liberal Leader who voted for the ICAC establishing legislation, was quoted on ABC TV describing the commission as a "Star Chamber" that "trashes peoples' reputations".

[53] Professor Peter van Onselen also questioned the "Star Chamber" nature of the commission and its history of "besmirching reputations".

[49] Nick Di Girolamo, a witness before the ICAC in proceedings that led to the resignation of O'Farrell, lodged a complaint in 2014 with the NSW Bar Association about Watson's behaviour during the hearings.

[57][58] On the other hand, in an editorial in the wake of the O'Farrell resignation, the Sydney Morning Herald quoted new NSW Premier Mike Baird that "ICAC is doing exactly what it should do and it is something that I will sign up to 100 per cent"; the newspaper advocated creation of a federal equivalent.