Opposition workplace relations spokesman Eric Abetz.

Employment Minister Eric Abetz. Photo: Glen McCurtayne

The royal commission into union corruption and slush funds is unlikely to lead to criminal convictions if high-level observations of conservative predecessors in the early 1980s are a guide.

Cabinet papers from 1982 reveal that, in the midst of its Costigan Royal Commission on the Painters and Dockers Union, Malcolm Fraser's Coalition government had grown sceptical about the effectiveness of such inquiries.

''Royal commissions produce reports but little comes out of them on which prosecutions can be based,'' the papers from the National Archives read.

Cabinet concluded that the notorious dockers' union was an ''organised criminal group'' and that the emergence of organised crime in Australia called for a new national crime commission.

This led to the National Crime Authority founded by the Hawke Labor government, which replaced the Fraser government the following year. It evolved into the Australian Crime Commission.

Labor has seized on the Fraser cabinet papers to question the Abbott government's motives for its sweeping royal commission into union corruption and slush funds.

The inquiry was triggered in part by reports in Fairfax Media of the misuse of union ''slush funds'' and resources and corruption in the building industry.

Opposition employment spokesman Brendan O'Connor, who has described the Abbott inquiry as a political ''witch-hunt'', said investigations of any illegal activities by unions should be carried out by law enforcement agencies.

''The Fraser government knew that royal commissions were not effective in dealing with allegations of criminal activity, that's why we now have the Australian Crime Commission. If Tony Abbott wants results rather than political point scoring he needs to rethink this royal commission,'' he said.

At the weekend Fairfax reported that senior labour movement insiders were privately co-operating with the Abbott government for the royal commission. Employment Minister Eric Abetz confirmed his office had received information from union officials about corruption and questionable financial arrangements.

As well as growing doubt about the bite of royal commissions, the Fraser government cabinet papers query the ability of international crimes commissions of the time to deal with corruption. ''Crimes commissions in the form in which they operate in the US appear to have limited success so far as actual prosecutions are concerned.''

One issue, the cabinet papers say, was that law enforcement staff were not then qualified to deal with organised crime.

Mr O'Connor said that the millions to be spent on the Abbott royal commission should be redirected away from the lawyers set to makes millions from the inquiry to the crime commission and other police agencies to boost their effectiveness. ''If we were trying to fight crime we'd be giving the money to the Australian Crime Commission,'' he said.

The inquiry into the Painters and Dockers Union also had some unintended consequences, with a major exposure of tax rorts by key business figures, including big Liberal donors.