The Trans-Adriatic Pipeline would move natural gas from the Caspian region to European markets. It would start near Thessaloniki, Greece, go through the Adriatic Sea and reach shore in southern Italy.
The project consortium announced that it started its Environmental and Social Impact Assessment process in Greece by submitting its so-called scoping report to the Athens government.
"Today's submission is an important step toward the realization of the TAP project and reflects the huge amount of preliminary engineering work and stakeholder consultation that we have already carried out in Greece," said TAP country manager Rikard Scoufias in a statement.
The move follows similar action in Albania and Italy early this year.
"We will now study (the) route in more detail and will continue to consult all those affected so that any concerns can be properly addressed," added Martin Ferguson, health, safety and environment director at TAP.
TAP could come online by the time developers start shipping gas from the Shah Deniz II gas field in Azerbaijan in 2017.