An agreement signed last year making the Vatican's de facto recognition of Palestine in 2012 official has come into effect, the Holy See said on Saturday.

The Vatican signed its first treaty with the "State of Palestine" last June when it called for moves to end the Israeli-Palestinian conflict and backed a two-state solution.

"The Holy See and the State of Palestine have notified each other that the procedural requirements for [the accord's] entry into force have been fulfilled, the Vatican said in a statement on Saturday.

The UN General Assembly adopted a resolution in 2012 recognising Palestine as an observer non-member state. This was welcomed at the time by the Vatican, which has the same observer non-member status at the United Nations.

In October 2014, Sweden acknowledged Palestine, a decision that drew condemnation from Israel and led to tense relations between the two.

Israel has previously called the Vatican accord a hasty move that could damage prospects for advancing a peace agreement and impact its future diplomatic relations with the Vatican.

But the Holy See under Pope Francis is eager to have a greater diplomatic role in the Middle East, from where many Christians have fled because of conflicts in Syria, Iraq and other countries.

"The Agreement...regards essential aspects of the life and activity of the Church in Palestine, while at the same time reaffirming the support for a negotiated and peaceful solution to the conflict in the region," the Vatican said.