The Australian Competition and Consumer Commission (ACCC) says that Australia's major airports need to invest more to overcome looming congestion issues.
The ACCC made the statement in its airport monitoring report for 2011-12, which measures the service quality of Perth, Melbourne, Brisbane, Sydney and Adelaide airports against their financial performances.
The report shows that the overall service quality at the airports decreased compared with the previous year as passenger numbers at all the airports, except Adelaide, grew strongly.
The ACCC says that there are already signs of increasing congestion at the airports as the proportion of on-time flight movements has fallen over the past 10 years. It also warns that "the absence of additional investment may lead to possible capacity constraints in the future".
"It is apparent that continued growth in passenger numbers at most airports is placing pressure on existing aeronautical infrastructure, contributing to lower service standards," says ACCC chairman Rod Sims. "More investment is required to avoid excessive congestion, and ensure that the needs of Australia's travellers can be adequately accommodated."
A number of Australian airports have planned to invest in more airside infrastructure and passenger terminals to cope with future growth, although not without controversy.
Brisbane airport is planning to build a new parallel runway that will help to ease congestion, but is currently in a dispute with airlines over the levying of a development fee on passenger tickets to fund its construction.
Other airports, such as Melbourne and Perth, have already started on large capital expenditure programmes to enhance the capacity of their terminals.
The ACCC adds that in future airport monitoring reports, it will "observe progress by the airports in undertaking planned aeronautical investment".