The value of the Ukrainian gas transport system (GTS) would fall by 80% if Russian gas transit to Europe is fully halted, Board Chairman of national joint-stock company Naftogaz Ukrainy Andriy Kobolev has said.

"Mainly the value of the Ukrainian gas transport system is determined by the factor is we have transit after 2019. The figure will vary from billions to dozens of billions," he said on 3s.tv channel late on Monday.

Kobolev said that the implementation of this scenario is possible if Nord Stream 2 and two sections of the Turkish Stream are built.

"If the Nord Stream 2 project and the Turkish Stream project with two lines are realized, I believe that no transit will be on the territory of Ukraine. I believe that it would cut the value of the Ukrainian gas transport system by some 80%," he said.

He said that from the economic point of view construction of the above-mentioned gas pipelines is unviable, as today there are many pipelines to transport gas and spending on the projects totals several dozens of billions of U.S. dollars.

Kobolev said that the company last week submitted an official complaint to the German regulator that decided to expand Gazprom's access to the OPAL gas pipeline.

"We are mulling the possibility of challenging the decision of the European Commission. There are three options, and one of them is via court," he said.