A legal expert says the Federal Government should look to WA when creating its national anti-corruption body.

The head of one of Australia's longest-serving corruption watchdogs says WA could offer guiding principles to avoid the federal body becoming “window dressing”.

For over seven years, John McKechnie has overseen the investigation of serious misconduct in Western Australia's public sector. He says there are some necessities for the federal corruption body.

“They must have the power to initiate inquiries themselves, they must not only rely on recommendations, they must have the ability to be retrospective and they must have the ability to fearlessly examine anything, wherever it comes [from],” he said.

He said the government needs to work out what happens when an anti-corruption body reaches the end of its investigation, and whether it should put forth opinions about whether actions amount to misconduct.

“An opinion which we sometimes form has no legal consequences, but clearly it has reputational consequences and it lets the public, who are actually paying for all of this, know what's happening,” he said.

Mr McKechniealso noted the practice of the New South Wales Independent Commission Against Corruption (ICAC) in taking evidence in private, and then again in public.

“I think you can see what ICAC has done over the years, and it's not something that I would follow,” Mr McKechnie said.

The current WA model has all of the features Mr McKechnie recommended, but he says he hopes a review into the state’s laws will give the Corruption and Crime Commission (CCC) one of its previous functions back.

Until 2015, WA’s CCC was also responsible for educating the public sector about corruption, but now it is only required to investigate it.

“In practice, we often see matters which would be good examples of education in corruption prevention,” he said.

“But we're somewhat constrained now in reporting on those, generally because we no longer have that power.”

Mr McKechnie said WA could also improve the way it deals with lower-level misconduct.

“I think there's a gap in data collection, so that we're not entirely sure what or how big a problem we might have in misconduct,” he said.

“We can only work, as can the Public Sector Commission, on reports, so that doesn't necessarily give a true picture.”