DOHA: Energy-rich Qatar will open on April 1 a new airport with a capacity to handle 30 million passengers, as the Gulf state vies to increase its share of transit air travel, an official said Monday.

"The annual capacity of Hamad International Airport will be 30 million passengers when it opens on April 1," the head of Qatar's Civil Aviation Authority Abdul Aziz al-Nuaimi told AFP.

He said the cost of building the new hub over nearly eight years has "exceeded $15 billion."

Eleven foreign budget carriers will be the first airlines to use the new facility, while the emirate's flag carrier, Qatar Airways, joining in the second quarter of 2013, he said.

The new airport spreads over 29 square kilometres (11.2 square miles), and features two runways stretching 4.85 kilometres (three miles) and 4.25 kilometres (2.64 miles) respectively.

The terminal has a total surface of 60 hectares.

The new airport, which replaces the old Doha International, is expected to raise its capacity to 50 million passengers per year by 2020.

Qatar Airway is one of the fast growing carriers which like neighbouring Gulf carriers -- Dubai's Emirates and Abu Dhabi's Etihad -- vies to increase its share of transit travel between Europe, Asia and Australia.