A planned meeting between rival Cypriot leaders scheduled for Thursday has been called off as a war of words over a nationalist commemoration in Greek Cypriot schools threatens reunification talks.

The government of Greek Cypriot leader Nicos Anastasiades said he had been informed on Wednesday that the meeting would not go ahead, and this was later confirmed by the United Nations which has been hosting the talks.

The row threatens nearly two years of UN-backed negotiations on ending the island's decades-old division that many had seen as the best chance for a settlement since Greek Cypriots rejected a UN reunification plan in 2004.

A meeting last Thursday broke up in acrimony with Anastasiades and his Turkish Cypriot counterpart Mustafa Akinci accusing each other of walking out.

The office of the UN spokesperson in Cyprus said Thursday's meeting "will not take place as planned" and that "new dates will be announced in due course".

UN envoy Espen Barth Eide "continues to work with both leaders, who have stated their commitment to the process," it said in a statement.

The head of the UN peacekeeping force on the island, Elizabeth Spehar, had shuttled between the two sides to try to broker a compromise, meeting Akinci on Tuesday and Anastasiades on Wednesday but to no avail.

Anastasiades said the meeting's cancellation was regrettable and that he remained ready to return to the table.

"I regret the decision of Mr. Akinci not to attend the meeting tomorrow. I am ready to continue the dialogue at anytime," he said on Twitter.

Akinci's spokesman also confirmed the cancellation.

The Turkish Cypriot leader himself said the negotiations had stalled primarily because of the Greek Cypriots' refusal to accept political equality in a federation under a reunification deal.

"There is no possibility of being preoccupied with minority and majority partners in a federation," Akinci said at a joint news conference with visiting Turkish Foreign Minister Mevlut Cavusoglu.

He urged the United Nations to play a greater role in resolving the crisis.

Tensions have soared over the February 10 approval by the Cyprus parliament for Greek Cypriot schools to commemorate a 1950 referendum on "Enosis", or union with Greece.

The unofficial referendum -- staged before Cyprus won independence from colonial ruler Britain -- overwhelmingly approved Enosis but had no legal value.

The amendment to schools legislation, sponsored by the far-right Greek nationalist ELAM party, essentially calls for secondary students to mark the anniversary by learning about the referendum and the Enosis cause.

- 'Mistaken decision' -

Akinci's spokesman said he was ready to return to the negotiating table but that steps first needed to be taken to overturn the amendment.

"I hope that in the shortest time the necessary steps are taken and a new date is set," the spokesman said. "We expect concrete steps at a political and administrative level to invalidate this mistaken decision."

The office of Turkish President Recep Tayyip Erdogan said the move by the Cyprus parliament was proof that the Turkish Cypriot minority on the island needed to retain the security guarantee of Turkey's military presence.

"This decision (on Enosis) once again confirms how important our attitude is on security and guarantees," spokesman Ibrahim Kalin said in Ankara.

He said it was up to the Greek Cypriots to put the reunification talks back on track. "The side that has to take a step is the Greek side," he said.

Akinci had warned on Monday that he could not continue the talks without action on an issue he said had caused "public indignation" among Turkish Cypriots.

"The Greek Cypriot leader should give a clear message to the Turkish Cypriot people and to the world that he does not support this decision," he said.

But Anastasiades retorted that Akinci was threatening the whole talks process on the pretext of a "minor" issue.

Cyprus has been divided since 1974 when Turkish troops invaded its northern third in response to an Athens-inspired coup seeking union with Greece. Ankara still has tens of thousands of troops deployed in the north.

Anastasiades heads the island's internationally recognised government. Akinci heads a breakaway administration which is recognised only by Turkey.