Turkey plans to build what it said would be the largest airport in the world in Istanbul, eventually able to handle 150 million passengers per year, in a project seen costing more than 7 billion euros ($A8.8 billion).
Transport Minister Binali Yildirim said on Wednesday the deadline for bids to build the airport, which will be Istanbul's third and have a total of six runways, would be May 3. It was not clear when the contract would be awarded.
The airport will add vital capacity in the region and enhance the role of Istanbul, the hub for flag carrier Turkish Airlines.
"At full capacity the new airport will be the largest in the world in terms of passengers," Yildirim told a news conference in Ankara. "We calculate the whole project will cost more than 7 billion euros excluding financing costs."
Turkey's economy, the fastest-growing in Europe, has advanced rapidly over the past decade under the leadership of Prime Minister Tayyip Erdogan and become a major trading partner with Europe and the Middle East.
The tender will be for a 25-year lease in a four-stage project, with annual capacity of 90 million passengers planned for the first stage, Yildirim said.
"The final annual capacity of the airport will be 150 million. The first stage will be operational in 2017," he said.
The tender advertisement will be published in Turkey's Official Gazette on Thursday.
Prime Minister Erdogan said on Tuesday the tender would be launched on Thursday with the first stage of construction to be completed in 3-4 years.
Turkish airport operator and builder TAV and construction company Limak are among the companies that have expressed interest in bidding for the contract.
TAV also has the operating rights for Istanbul's Ataturk airport, the country's largest, until 2021. It said the Turkish airports authority would compensate it for any losses if the third airport opened while it was still running Ataturk.