The only bid submitted to build an airport on the island of Crete was priced at 480 million euros ($509.42 million), well below the expected 850 million, sources close to the project said on Wednesday.
The bid was submitted last year by a joint venture of India's GMR Infrastructure and Greek construction group GEK TERNA.
"The financial offer was unsealed on Tuesday," one of the sources told Reuters on condition of anonymity.
Greece has made several attempts to build the airport at Kasteli since 2010 but the country's seven-year debt crisis has made it difficult to attract investors.
One source said the evaluation process was expected to conclude next month. The infrastructure ministry was not available for immediate comment.
The public-private partnership project, which the ministry had estimated would cost 850 million euros, will replace the ageing Heraklion airport.
Greece's second largest airport, it handles nearly six million tourists a year.
Tourism is an important source of revenue for the Greek economy. The country expects 27 million visitors this year, up from 25 million last year.
The winning bidder is expected to operate the airport for 37 years.