Synaspismsos, the New Left party in Greece (SYNASPISMOS=coalition of the left of movements and ecology) has been struggling for a mutual reduction of the military budgets of Greece and Turkey. This campaign was launched during the 4th European Social Forum in Athens (May 2006) in cooperation with the Turkish party ODP (Freedom and Solidarity party) and was later joined by Greek and Turkish workers’ Unions. You can follow the development on English section.
While this position was never even considered by the Greek government I saw a relevant article in Die Zeit of Hamburg (11 January 2012)