The 4 km (2.5 mile) stretch of road winding through hills seeks to link one of the most remote regions in northwest Cyprus in an area hemmed in by the sea, towering mountains and a closely-patrolled truce line dividing the two sides for decades.
In a carefully choreographed ceremony in United Nations no-man's-land, the Greek and Turkish Cypriot leaders cut a ribbon, sipped coffee at breakneck speed in hamlets lying on either side of the line, and pledged to work for peace.
"Today's opening is an encouraging signal ... We are witnessing another example of this pursuit of peace and another difficult barrier has gone," European Union Enlargement Commissioner Stefan Fule said at the brief ceremony.
The new checkpoint is the seventh between the two sides of a United Nations-controlled cease-fire line established in 1974 on the eastern Mediterranean island.
Argentine peacekeepers monitor a buffer zone in the northwest spanning valleys and mountains and where moufflon, Cyprus's timid and indigenous wild sheep, roam in herds.
Ethnic conflict hit the region, known as Tylliria, in 1964 and the free flow of traffic stopped. Turkey invaded northern Cyprus 10 years later in response to a brief Greek Cypriot coup engineered by the military junta then ruling Greece.
Cyprus joined the EU in 2004, represented in the bloc by its internationally recognized Greek Cypriot government in the south of the island that opposes Turkey joining the bloc until the conflict is resolved.
The Greek and Turkish Cypriot communities started peace talks in 2008, the latest in a series of bids to crack one of the world's most enduring conflicts.
In New York, a spokesman for UN Secretary-General Ban Ki-moon said: "The Secretary-General hopes that this will help strengthen the climate of trust and goodwill necessary for the UN-supported negotiations to achieve a mutually acceptable and lasting settlement as soon as possible." Both sides agree in principle to reunite Cyprus as a two-zone federation. But there are disagreements on issues ranging from power-sharing to the rights of thousands of internally displaced people and how much territory each side will retain in a deal.
