Former Qld Labor ministers accused of political interference at CFMEU inquiry

The Commission of Inquiry into the CFMEU has finished its tenth block of public hearings. (ABC News: Luke Bowden)

The Commission of Inquiry into the CFMEU has heard allegations that former Labor ministers Mick de Brenni and Grace Grace intervened in operational matters at Queensland's building regulator and Office of Industrial Relations.

The inquiry also heard the CFMEU would often write directly to government ministers with complaints.

When Graeme Easterby referred allegations of Construction, Forestry and Maritime Employees Union (CFMEU) interference at Queensland's building regulator to the Crime and Corruption Commission (CCC) he expected a rigorous investigation.

Instead, he said politics prevented the matter from progressing.

"I clearly remember they [CCC officials] said they didn't see it going anywhere while the [Labor] government is in power," Mr Easterby, a former Queensland Building and Construction Commission (QBCC) licensing manager, told the long-running commission of inquiry into the CFMEU.

The probe has wrapped up its tenth block of public hearings with explosive new allegations of political interference levelled against senior Palaszczuk government ministers Mick de Brenni and Grace Grace.

Steven Miles has maintained his support for Mick de Brenni and Grace Grace. (ABC News: Lucas Hill)

"We should be cautious in taking them as fact," Mr Miles told reporters in Mackay on Thursday.

"Where those individuals named get the opportunity … they will be able to put their own side of those stories and … get the opportunity for their lawyers to interrogate those witnesses."

He maintained his support for both Mr de Brenni and Ms Grace.

In his testimony on Wednesday, Mr Easterby suggested the CFMEU wielded influence over the highest levels of the QBCC, including then-commissioner Brett Bassett and the board.

The inquiry heard ousted former CFMEU leader Jade Ingham was appointed to the QBC board in 2018, around the same time Mr Easterby arrived at the regulator.

Graham Easterby suggested the CFMEU wielded influence over the highest levels of the QBCC. (Supplied)

Mr Easterby said the CFMEU would often write directly to government ministers, including then-public works and procurement minister Mr de Brenni, complaining about non-union contractors.

Mr Easterby told the inquiry Mr Bassett admitted that the QBCC was "under pressure" from both Mr Ingham and Mr de Brenni to investigate and take licensing action against certain contractors.

"I was a little dumbfounded," Mr Easterby said, adding that regulators were "meant to be independent".