Mr Levine also wants consideration of an "exoneration protocol" which would allow people found corrupt by ICAC but who are not later convicted on criminal charges to have the records "expunged" or the finding set aside by the Supreme Court.

The recommendations are contained in Mr Levine's long-awaited report on ICAC's powers delivered to Premier Mike Baird on Thursday.

Mr Levine was asked by Mr Baird to review ICAC's powers following the report of an expert panel comprised of former chief justice of Australia Murray Gleeson and barrister Bruce McClintock, SC, in July last year.

It followed ICAC's aborted inquiry into whether Crown Prosecutor Margaret Cunneen attempted to pervert the course of justice by counselling her son's girlfriend, Sophia Tilley, to fake chest pains after a car accident to avoid a breath test.

The ICAC aborted the inquiry after the High Court ruled it was outside its jurisdiction and the NSW department of public prosecutions did not proceed with charges.

Among Mr Levine's other recommendations are that people called in for compulsory questioning should as a general rule be told about the nature of the allegation or complaint being investigated and the office of the Inspector of ICAC should have stronger oversight powers.

These included the office being made a full-time position with its own staff and being informed of "all assessments" made by ICAC in relation to whether or not to investigate a matter as well as the outcome and reasons for the decision.

But the recommendations for an end to public hearings and creation of an exoneration protocol are by far the most contentious as they are at odds with the Gleeson/McClintock panel report.

The expert panel's report did not recommend changes to the ICAC's power to hold public inquiries.

It also advised against introduction of "formal oversight or internal review of decisions to hold public inquiries or decisions as to what witnesses to call at public inquiries".

However, Mr Levine argues that removal of public hearings would mean "the not uncommon criticism of public hearings as theatre and the cause of disproportionate reputational damage will be eliminated".

He notes that former ICAC inspector David Ipp had argued that public hearings are one of the watchdog's "most important weapons" in uncovering corruption.

But Mr Levine said that if hearings are in private then "at the end of the whole investigation, if no corrupt conduct is found - nobody is hurt".

"Equally, if at the end, serious corrupt conduct is found, it publicly can be exposed in relation to specified individuals and identified conduct," he says.

An exoneration protocol should be considered because those found corrupt by ICAC but not convicted in the courts "have no recourse to repair the impact of the ICAC public inquiry and it is likely that their names will always be associated negatively with an ICAC inquiry."

"The more so by the perpetual archival of public and social media," the report states.

In a statement, the ICAC said it agreed with the Gleeson/McClintock panel's comment that public inquiries " ...serve an important role in the disclosure of corrupt conduct [and] in disclosing the ICAC's investigative processes".

Mr Levine flagged his recommendation for consideration of an exoneration protocol during hearings of the parliamentary oversight committee for ICAC in March.

The inquiry was held after an earlier report by Mr Levine found the ICAC's inquiry into Ms Cunneen was a "low point" in the ICAC's history and the agency had engaged in "unreasonable, unjust [and] oppressive maladministration".

The ICAC hit back, saying Mr Levine's report contained legal and factual errors.

Mr Baird has said Mr Levine's latest report will be considered by the parliamentary inquiry, which is due to report later this year.