Perth Airport was warned 18 months ago about the unprecedented growth that has gridlocked the airport and which Qantas claims is costing it $10.8 million a year.
The Chamber of Minerals and Energy said yesterday its 2011 WA State Growth Outlook released in April last year, accurately forecast the boom in air travel requirements for the resources sector.
Chamber director Damian Callachor says the industry body "cannot understand the mismatch in their forecasting given the growth figures we are supplying from our members".
"Perth Airport is too conservative and not meeting requirements to facilitate trade," he said.
"We urge the airport to future-proof the State's economic future."
On Tuesday, Qantas chief executive Alan Joyce supported calls from Treasurer Troy Buswell in _The Weekend West _for a third runway - and second parallel - at Perth Airport to solve the congestion issues.
Qantas put a dollar figure of $10.8 million on the delays - inbound and outbound - which often last 45 minutes and sometimes longer.
Airline analysts said the cost to all airlines at Perth Airport would be $24 million in wasted fuel, extra crew and staff hours.
Perth Airport chief executive Brad Geatches said the airport had the "capacity and the preparedness to construct the third runway, if the airlines using Perth Airport want it to be brought forward".
Mr Buswell said he was concerned with Perth Airport's planning models and he expected the State Aviation Review, which should report by December, to give firm benchmark growth projections.
Last week, Mr Buswell criticised Perth Airport, saying it was an impediment to the State's growth.
Yesterday, he said he was concerned over the $600 million price tag cited by Perth Airport to build another runway that would future-proof the airport.
And Mr Callachor said fly-in, fly-out demand would increase as construction phases ended because production roster rotations would be more frequent.
"We are finding that more staff want to work on FIFO shifts and that the trend is for more frequency of rotations, thus increasing demand," he said.
"There is also another $200 billion in resource projects committed and yet to start."