"Commissioners are answerable to ministers as any other CEO in the public sector. The stuff that is going to embarrass government is going to be hidden in official documents or statistics."
He said it was easier to refuse access to information that would otherwise be made public.
Universities New Zealand, the body representing the country's eight universities, said it was working to identify whether there was a trend affecting researchers' work.
Universities NZ chairwoman, Professor Harlene Hayne, said academics and other researchers needed access to data for their work, which drove innovation and economic growth and helped find and fix social issues.
"As academics we accept that research data needs to be confidential and anonymised so that individuals cannot be identified. But we do not accept constraints on the findings, or the publishing of unfavourable results."
Dr Rod Carr, vice-chancellor of the University of Canterbury, backed Dr Gilbert's decision to make the issue public. He said debate touched on issues of academic freedom and the statutory obligation in the Education Act for academics to be the "critic and conscience of society".
Any government agency receiving a request for research information should apply the Official Information Act, Dr Carr said. If information sought was not able to be obtained through the act because of reasons in the legislation, then researchers should negotiate access, he said.
The police ban included telling Dr Gilbert he could not access the data because he was "associated with gangs". Dr Gilbert, who specialises in research on gangs, said he had been told the personal ban was being reconsidered and he would learn the outcome next week.
Police have stood by the conditions in the "blacklist" contract, saying no researcher has yet been banned. But the changes left in almost all the most controversial aspects that have sparked accusations of threats to academic freedom.
A spokesman for Police National Headquarters said there was an "ongoing review".
