The new head of the Australian Building and Construction Commissioner, Leigh Johns, will have some explaining to do in a fortnight when he attends his first Senate Estimates hearings after the remarkable case of a Western Australian police officer infiltrating a union meeting came to light last week.

The Commission and WA Police have yet to explain how a police officer attended a CFMEU meeting in Karratha undercover and reported on the meeting to the ABCC. WA Police have admitted that the police officer, who allegedly was there in plainclothes for the purposes of public safety, failed to follow necessary reporting protocols and was, in the words of WA Police Commander Fred Gere, “drawn into a situation that really a police officer shouldn’t have been drawn into”. The ABCC is taking action against CFMEU state assistant secretary Joe McDonald on the basis of the officer’s report.

This is only the latest in a list of incidents involving the ABCC’s use of its draconian powers to pursue a campaign against the CFMEU. It has threatened to jail a Melbourne academic whom it compelled to attend an interrogation over a dispute on a building site the man had seen while walking past. It tried and eventually failed to prosecute CFMEU official Noel Washington for failing to obey a summons to be interrogated about a union meeting held outside work hours. And it is currently pursuing the apparently arbitrary prosecution of South Australian CFMEU member Ark Tribe for failing to attend a hearing.

Former commissioner John Lloyd defended the Commission at Estimates this year by saying: “We respond to complaints. We do not go on fishing expeditions.” That might explain the Commission’s curious inactivity after the CFMEU’s NSW headquarters was firebombed in May, only contacting the union about the incident two weeks later — the day before the Commission was due to appear at Estimates.

The ABCC’s vendetta against the CFMEU has proceeded while — as tragically predicted by a major employer group in 2004 — there has been a huge increase in deaths in the building industry, up more than 30% between 2004 and 2008, and sham contracting in the building industry has cost taxpayers hundreds of millions a year in lost revenue. Until Labor Senator Doug Cameron raised the issue at Estimates in 2009, the Commission had routinely fobbed off complaints about sham contracting to the Fair Work Ombudsman, despite having statutory responsibility for the issue.

Lloyd’s term expired last week, after he refused to apply for a second term as ABCC head because, he said, he thought he shouldn’t have to go through a selection process. Lloyd had previously criticised the government for being insufficiently sensitive about his reappointment.

Johns starts as his successor next Monday, meaning he’ll barely have got his feet under the desk before having to front up to a grilling by Labor senators. He has previously been deputy commissioner, but moves to the job from the role of special counsel at the Fair Work Ombudsman.

The Commission has a large number of ex-police officers working for it and the CFMEU says it is implausible that there was no planning of the undercover infiltration of the meeting between the WA Police, which has denied involvement, and ABCC staff.

“It’s passing strange that the police sought to secure the peace at a public meeting by sending a plain clothes officer in,” CFMEU construction division head Dave Noonan told Crikey this morning.

Noonan wrote on Friday to new Workplace Relations Minister Chris Evans calling for an independent inquiry into the incident and whether the ABCC is using law enforcement officials for covert monitoring elsewhere. Labor promised before the 2007 election to abolish the ABCC but instead opted to transfer most of its powers to a new Building Industry Inspectorate. The relevant legislation failed to pass before the election.