A consortium made up of seven of the Philippines' largest conglomerates has proposed a 350 billion pesos (US$6.7 billion) plan to modernise and more than triple the capacity of the country's over-stretched international airport.

The group comprised of Metro Pacific Investments Corp , JG Summit Holdings Inc, Alliance Global Group Inc, Filinvest Development Corp, Aboitiz InfraCapital Inc, Ayala Corp's AC Infrastructure Holdings Corp and LT Group Inc's Asia's Emerging Dragon Corp, has tapped Singapore's Changi Airports International to provide technical support for the proposed project.

The project, which involves the building of an additional runway and passenger terminals, would turn the Ninoy Aquino International Airport (NAIA) into a "fully-integrated premier gateway," consortium spokesman Jose Emmanuel Reverente told a media briefing, adding the proposal was submitted on Feb. 12

Airlines and passengers suffer chronic delays because of congestion at the airport, which served more than 40 million passengers last year, compared with its designed capacity of 30 million.

The Philippines is one of Asia's fastest-growing economies but its infrastructure has become a logistical headache due to government under-spending.

Philippine President Rodrigo Duterte has promised to address that through a US$180 billion "Build, Build, Build" infrastructure campaign.

His government has said it is open to unsolicited proposals to help jump-start projects, but they would be subjected to a Swiss Challenge where other bidders are asked to compete and the original proponent is allowed to match the best proposal.

NAIA would be able to serve 65 million passengers once the first phase of the proposed project is completed, Reverente said, with potential capacity expected to reach up to 100 million under the second phase of the plan.

The proposal also includes an automated people-mover that would link all three terminals and connect NAIA to the existing mass transport system in Metro Manila, Reverente said.