An expert on the mafia says big public works are big targets for organised crime.

Organised crime expert Dr Anna Sergi says criminal groups use public contracts both for profit and to clean dirty money.

She spoke on Victoria's Independent Broad-based Anti-Corruption Commission's podcast this week, ahead of an address at IBAC’s corruption prevention conference in October.

She said organised crime is constantly trying to find its way into corrupt government.

“Whenever there is investment, there will be organised crime attempts to hijack that investment,” she said.

“I do not believe in the distinction between organised crime, especially mafia-organised crime, and corruption. I think they are the same phenomenon.”

Dr Sergi said major public construction contracts in particular attract criminals.

“Construction is definitely the one that every jurisdiction everywhere in the world will have problems with when it comes to organised crime,” she added.

She said that in order to prevent corruption, the bar for which cases to investigate needs to be lowered from high level “serious” matters to lower level, general unethical behaviour.

“Infiltration from criminals into the public sector is not a one-way street,” Dr Sergi said.

“There are people at every level, in every position, private sector, public sector, who are happy to behave unethically.

“It always starts in my experience with very simple personal transactions, personal bias.”