The contractor was awarded the HK$4.2bn (£353m) contract by Cathay Pacific and its joint venture partner Hip Hing Construction.
The new terminal, which is approximately 280,000 square metres, is scheduled for completion in 2013.
Balfour Beatty chief executive, Ian Tyler, said: “We are delighted to have been awarded this contract to enhance Hong Kong’s status as an international airfreight hub. Along with our joint venture partner, we are committed to the delivery of a terminal of the highest quality, while maintaining excellent standards of safety.”
Balfour Beatty has been a major player in the development of Hong Kong International Airport, having been responsible for the construction of an £800m terminal building completed in 1998.