The resources industry is headed for a massive changeover in its workforce as hordes of construction workers building the State's mega projects make way for operational personnel.
The Chamber of Minerals and Energy is projecting worker numbers to peak at 125,000 in two years' time - from 116,000 now - before dropping below current levels.
The forecasts are contained the chamber's 2013 State Growth Outlook produced with PricewaterhouseCoopers, due for release today.
CME chief executive Reg Howard-Smith said construction periods of the liquefied natural gas projects Gorgon and Wheatstone, as well as Rio Tinto's iron ore expansion were set to last longer than predicted two years ago.
But in 2014 and 2015 the move from construction to production would see a smaller but more skilled workforce in the sector.
Mr Howard-Smith said in order to attract new projects, governments needed to address the factors which had made Australia the second-most expensive place in the world for resources companies.
"We're saying look what's happening now and let's plan for the change," he said.
Mr Howard-Smith said expansion delays or cancellations by BHP Billiton and Fortescue Metals Group had not had much impact on the chamber's projections.
While the number of workers overall will eventually decline along with the proportion of fly-in fly-out employees, the pressure on Perth's airport won't be easing any time soon.
The CME is tipping an additional 640,000 resources sector passengers to be flying by 2017, with most commuting during peak periods.
Mr Howard-Smith said that was because the rosters of operations personnel had a quicker turnaround than the schedules of their construction counterparts.
The outlook showed mining and energy will continue to make high demands of the State's power and water resources.
The CME said electricity consumption in WA could increase 52 per cent by 2018, mainly because of resource projects.