Deputy prime minister Marcel Ciolacu said contracted works include 478 km of pipeline and three compression stations.
The cost of investment estimated at EUR480 million, of which EUR180 million non-reimbursable funding.
The pipeline will be able to carry 1.75 billion cubic meters of gas from Bulgaria and Romania to Austria by 2019 and 4.4 billion once the second stage is completed in 2022.
On September 28, officials of all four partner countries developing the pipeline project signed a memorandum in Bucharest to go ahead with the project and works should start in spring 2018.