A Syrian official made the announcement on Friday but did not give a reason for its refusal to abide by a 1999 protocol which paved the way for people to visit relatives on the other side of the border.
Dozens of extended families in the largely rural area were separated when Turkey's south-eastern border was drawn up in the early 1920s following a war of independence.
For years, relatives were forced to see each other and pass gifts through barbed wire marking the border.
The 1999 protocol allowed people to cross the border near the Turkish village of Ceylanpinari without a visa for 48 hours to visit relatives.
Each country was to host the event alternately and it was Syria's turn this year.
Turkey and Syria have had tense ties in the past, reaching a peak in 1998 when Ankara threatened military action if Damascus continued to shelter Kurdish rebel leader Abd Allah Ocalan and his armed fighters.
Tension eased in October of that year when Ocalan left Damascus, his long-time safe haven, and Syria pledged to stop harbouring the rebels, allowing a significant improvement in relations.
Bilateral ties have further warmed in the wake of the US-led war in Iraq.
The two countries, as well as Iran, share concerns that any move towards self-rule by the Kurds in northern Iraq could spark unrest among their own Kurdish minorities.