Congestion at Perth Airport and a lack of runway capacity are costing the airline industry and its passengers an estimated $72 million a year, according to a State Treasury report.
The figures come as Perth Airport confirmed yesterday that passenger numbers jumped almost 10 per cent last month to a record 1.17 million, putting more pressure on the airport's infrastructure.
Treasurer and Transport Minister Troy Buswell, who commissioned the report, said the figures "further strengthened the case for a third runway".
"This analysis shows that congestion has an adverse impact on the economy, business and individuals," Mr Buswell said yesterday.
"While the runway issue is not the sole driver of congestion it shows that Perth Airport needs to build a third runway as soon as possible."
However the report does not include the flow-on costs imposed on businesses and individuals affected by flight delays.
The resources industry standard for lost production at a mine site is $100,000 an hour.
"Clearly the real cost to the economy is much higher," Mr Buswell said.
Chamber of Minerals and Energy manager of people strategies Bruce Campbell-Fraser said it was extremely important to get staff to mine sites on time and well rested.
"The cost of delays is dramatic when managing changeovers," Mr Campbell-Fraser said.
Treasury said 20 per cent of scheduled flights in and out of Perth were delayed 30 minutes, which is similar to the US.
The delay figure did not include charter flights which carry most fly-in, fly-out workers.
Perth handled 140,000 flights in the past financial year.
Passenger and plane traffic through Perth Airport has grown about 40 per cent in the past five years.
A Perth Airport spokesman said he could not comment because it had not seen the Treasury report.
Last year the airport committed to the process to build the third runway, but it is expected to take at least four years because of the lengthy environmental approvals process.
The airport, air traffic control provider Airservices and airlines are also working through a program to increase the efficiency of the airport's operations, which is designed to eliminate delays in the afternoon. But according to Airservices, the morning demand for flights can only be met by a third - and second parallel - runway.
From next month, Perth Airport will introduce a slot system for weekday morning flights to eliminate the chaos of planes queuing for up to 45 minutes.