The Construction, Forestry, Mining and Energy Union already has its members’ approval to take protected industrial action against LNG plant builder Bechtel on the island with the union only needing to provide three days’ notice to take action ranging from overtime bans to work stoppages for indefinite periods.

“One source suggested the CFMEU was planning an indefinite strike from Thursday which, while only affecting crane operators, would disrupt all work across the three projects,” the Australian Financial Review reported.

Last month Macquarie Private Wealth flagged that crane-halting tactics were on the cards.

“This appears to relate to the crane operators who caused an eight-day stoppage at Pluto in April 2011,” MPW said of the CFMEU’s planned industrial action.

With the enterprise agreement expiring in June, the CFMEU has mainly been campaigning for a more family-friendly roster of three weeks on and one week off with Bechtel fighting to keep the existing four-and-one roster and associated schedules.

However, Bechtel has reportedly put up a revised EA that will be voted on over August 12-14.

“That revised accord includes two key concessions by Bechtel since a ‘no’ vote on June 3 to 5: it will cover three years instead of four and introduce a ‘three and one’ cycle in the second half of the third year, while a productivity payment set to begin in May 2015 would be brought forward to this November,” the AFR reported.

“Members of the other unions involved – the AMWU [Australian Manufacturing Workers Union], AWU [Australian Workers Union] and CEPU covering electrical workers and plumbers – are currently participating in protected action ballots, which close on August 19.”

Bechtel Gladstone general manager Kevin Berg told the Gladstone Observer: "We understand the key issue is moving towards a three and one roster.

"We are willing to go in that direction but not at this stage in the projects. To make that shift would be a huge impact on the number of people needed to maintain the workforce."

The revised EA reportedly needs 50% approval plus one vote of 8000 eligible employees to pass.

Bechtel has previously flagged locking out employees in regards to industrial action.

It has also warned the industrial action could affect workers who were not participating in it – which would be the case if cranes stopped operating.

Last week BG Group said industrial action could threaten the QCLNG project’s schedule of first LNG in late 2014.