The return of Mr Shorten from a week-long trip to Europe on Monday is expected to renew attacks by the Coalition on the issue of union misbehaviour and Labor's refusal to accept the re-establishment of the Australian Building and Construction Commission. Mr Abbott has sought to wedge the Opposition Leader by asking if he is ''on the side of law-abiding citizens or … people with a tendency to break the law''. Corruption fallout: Concern over Labor's union ties is expected to provide the Coalition ammunition against Bill Shorten (pictured) on the issue of union misbehaviour. Credit:Andrew Meares Prompted by Fairfax Media reports that officials at the Construction, Forestry, Mining and Energy Union had been bribed by corrupt companies for access to lucrative construction jobs, the government will widen its promised judicial inquiry into union slush funds. Mr Abbott is expected to make an announcement before Parliament returns next week, with speculation that the investigation will have the far-reaching powers of a royal commission. ACTU president Ged Kearney has dismissed a royal commission as a ‘‘witch hunt’’ and Mr Shorten – a former leader of the Australian Workers Union – will maintain calls for police to investigate alleged wrongdoing at the CFMEU rather than a labour movement-wide investigation.

But the latest scandal has revived discussion within Labor about democratic reforms, with some wondering whether Mr Shorten will take on union power in favour of the rank and file membership – an issue in the spotlight during the return of Kevin Rudd to the prime ministership and again during the Labor leadership election won by Mr Shorten. The Labor Party, particularly in opposition, is reliant on union money to finance its operations and campaigns. In return, unions dominate votes on the conference floor and powerful administrative committees at state and national level. A Labor source said of Mr Shorten: ‘‘People aren’t expecting him to put his weight behind those [union-related] issues.’’ On Sunday, a former Labor premier of Western Australia, Geoff Gallop, warned his party it underestimated the public sentiment against union influence at its peril. ‘‘They have to realise there is a world out there waiting for a genuine social democratic party,’’ he said.

AWU national secretary Paul Howes, a protege of Mr Shorten, said he would not comment directly on the poll’s result but said there was little evidence of any negative impact from the union movement on Labor. ‘‘For the first time in about five years, Labor is ahead in the polls under a leader in Bill Shorten who is closely associated with the union movement,’’ he said. John Graham, the left assistant secretary of NSW Labor, has been a voice for democratic reform but said unions remained a core element of the ALP. ‘‘Labor knows it needs to change to open its structures up, but without the unions Labor risks losing its original burning cause – lifting the fortunes of working people,’’ he said. Employment Minister Eric Abetz said Labor ‘‘is only interested in helping feather the nests of union bosses and the faceless men’’. ‘‘Labor is a product of the unions and Bill Shorten is a product of union deals and power plays. Labor will never change while the union bosses and faceless men are in charge,’’ he said.

Loading The poll found men were more likely to agree that Labor should cut ties (56.8 per cent) than women (48.4 per cent), and those aged over 65 were most likely to support the proposition (59.5 per cent). Follow us on Twitter