Unions probe divides on party lines

Support for the long-running trade unions royal commission is divided along party lines, with a new poll showing coalition voters have far more faith in the probe led by Commissioner Dyson Heydon than their Labor counterparts.

Just 42 per cent of the total respondents to an October Essential Media poll ranked the royal commission as "a legitimate investigation of union practices".

Taking voting preferences into account, opinions among the 1012 respondents to the online poll divided along party-political lines: 69 per cent of Liberal/National voters agreed with the commission's legitimacy compared to 22 per cent of Labor voters.

By contrast, 48 per cent of Labor voters ranked the commission as "a political attack on Labor and the unions" - a view supported by only 12 per cent of Liberal/National voters.

Greens voters opted for 41 per cent "attack" and 27 per cent "legitimate".

Overall opposition to the commission was low, with just 27 per cent of total respondents ranking the inquiry as a political attack.

General indifference to the commission was also high, with 31 per cent of all survey respondents having no opinion about it.

The overall results were similar to attitudes when Essential last asked the questions in August.

Commissioner Heydon will hold his last public hearings in November and is due to deliver his final report in December.