Currently FIFO staff work three weeks on, four weeks off, then three weeks on and five weeks off but under the new proposed agreement, employees would simply do a four week on, four week off roster. 

In a power-point presentation leaked to Energy News this week, Shell Australia said a new roster was needed due to interstate travel restrictions, and the combined impact of a 14-day quarantine requirement for FIFO staff. 

"This is placing significant pressure and strain on Prelude FLNG production team resourcing, as well as work-life balance for all personnel," Shell said in its proposal to its employees. 

"Interstate workforce are required to spend up to 66.7% more time away from home due to WA quarantine requirements." 

However unions have warned that this would increase fatigue among workers and fly in the face of other Australian FIFO agreements, which will remain with the initial model. Most other operators have moved to Shell's earlier model. 

Shell's big incentive is a $50,000 one-off payment to sign on to the new FIFO roster. 

Union members speaking to Energy News label it a "pay off" and said it would actually allow Shell to make some workers redundant and save money. 

Shell's human resources team disputed this and said the new roster agreement was intended to "provide significant economical and reputational benefit to the company." 

The leak of the proposed new working roster comes the same week that a coalition of unions, dubbed the Offshore Alliance, doubled down on its attacks on Shell management saying the company was unlawfully forcing its contractors to negotiate cheaper pay rates for workers. 

The unions are currently in bargaining negotiations for better wages and worker job security with two key contractors - Monadelphous and Sodexo. Some union members are currently on strike at Prelude. 

Shell has repeatedly refuted the suggestion it has interfered with negotiations with both Monadelphous and Sodexo workers. 

Now, the Offshore Alliance will attempt to force Shell to the bargaining table to lock in current EBA agreements and not the new proposed roster. 

According to the unions an "overwhelming majority" of Prelude workforce have signed a bargaining petition to begin new negotiations. 

The Offshore Alliance has filed what is known as a majority support determination to the Fair Work Commission. 

If successful Shell may be required to begin formal bargaining with its own workforce, while contractors Sodexo and monadelphous will continue their own EBA bargaining. 

"Shell recognises and supports the entitlement of all workers to exercise their rights to freedom of association and participate in union organised activity," a Shell Australia spokesperson told Energy News.