Hill International has won a one-year contract extension worth $78m for work on Muscat International and Salalah airports in Oman, the US-headquartered construction consulting firm said.

The contract, awarded by Oman’s Ministry of Transport and Communications and the Public Authority for Civil Aviation, marks an extension of a three-year, $108.5 million contract, awarded in 2012, to provide consulting engineering services for both airports.

The expansion of Muscat International Airport, the largest airport in Oman, includes a new terminal that will have a capacity of 12 million passengers annually.

Salalah Airport’s expansion will include upgrading it from a domestic hub to one suitable for international flights.

This will include building a new runway long enough to handle the Airbus A380 and a new terminal that will increase the airport’s capacity to one million passengers annually.

Mohammed Al Rais, the Middle East regional president for Hill International’s Project Management Group, said: “It is an honour to continue to serve the Ministry to help deliver these critical aviation projects. Upon completion, they will have an immediate positive impact on both business and tourism in the region.”