KIEV, Sept. 23 - About $5.3 billion of investment may be needed to overhaul and modernize priority elements of Ukraine's gas transportation system, the deputy chief executive of national oil and gas company Naftogaz Ukrayiny, Vadym Chuprun said on Thursday.

This money would be spent over a period of seven years, but timetables might be shortened in the course of project implementation, Chuprun said at the Energy in Ukrainian Industry exhibition in Kiev.