Fair Work has launched legal action against a CFMEU secretary accused of organising blockades.

Fair Work Building and Construction director Nigel Hadgkiss says the national building watchdog is looking for financial penalties to be laid against construction union leader Dave Noonan and two senior union officials, the three it alleges were behind a blockade at the new children’s hospital project in Perth in July last year.

Some reports say it shows escalating tension between the union movement and the Abbott Government.

The Australian Council of Trade Unions has condemned the move, which it sees as the LNP using independent tools to carry out its own anti-union work.

Mr Noonan has accused the workplace regulator of acting politically, to assist the Federal Government in its quest to restore the Australian Building and Construction Commission.

The FWBC action also lists the CFMEU‘s assistant West Australian secretary Joe McDonald, state secretary Mick Buchan, organiser Tawa Harris and the union itself as respondents.

It will be alleged that the blockade was strategically organised to stop a “critical concrete pour in a bid to coerce John Holland to agree to their enterprise agreement demands”.

Fair Work will claim that Mr Noonan knew how critical the concrete pour was to getting the project done, and that he caused the hold-up knowing it “would expose head contractor John Holland to significant financial detriment”.

Some reports say up to 600 people gathered at the new hospitals’ main site entrance, to block the concrete machinery.

The union representatives face up to six alleged breaches of industrial law, which would come with maximum penalties of $61,200 if upheld.

Fair Work says after the successful stopping of the crucial concrete, the blockade moved to a nearby park.

The watchdog alleges that once there, the union authorities said it would continue happening until they got their way.

‘This is not over, we are not finished with John Holland,” Fair Work claims Mr Noonan said.

“We send a clear message to everyone around here that’s here today that we can pull the numbers whenever we f**king need them and we’ll do whatever we need to do,” it alleges Mr Buchan told the crowd.

It will claim Mr McDonald said: “We don’t go back to work today”, “we will come back, and we will come back and we will come back” and “we are the union and we called the shots today”.

ACTU secretary Dave Oliver recently told News Corp reporters that the right to strike is recognised under international law by UN and International Labour Organisation Conventions, and as Australia is a signatory those rights must be protected.