ICAC secrecy rules have been in the spotlight after information about an investigation was revealed in September.
Attorney-General Vickie Chapman issued a statement linking ICAC to the matter, which prompted questions over whether she acted in breach of the ICAC Act.
Opposition spokesman Tom Koutsantonis also raised the topic in a parliamentary estimates hearing under the protection of parliamentary privilege.
Under questioning by Mr Koutsantonis on Tuesday, Mr Lander confirmed he did not give permission for Ms Chapman to issue her public statement.
"I didn't know she was going to make it," he said.
He added that he would be unable to investigate Ms Chapman's statement because he would be a witness.
Mr Lander went on to say state parliament should ensure it is not hindering ICAC investigations or the provision to protect people from reputational harm.
"It's time for parliament to consider whether it is appropriate for members to use parliamentary privilege to expose persons under investigation," he said.
The Commissioner said future investigations could be compromised by the premature disclosure of information if the rules are not clarified.
He said that disclosure could happen under parliamentary privilege or when there is pressure placed on a public officer.
"I agree that the public have a right to know, which is at the core of notions of public interest, but the right to know is not absolute," he said.
"As with most things, the devil is in the detail."
He also criticised reforms before parliament which would allow him to hold open hearings in maladministration cases.
"I think this bill might create the illusion of open hearings," he said.