Palestinian officials on Thursday appeared to backtrack on a pledge to make a fresh bid for upgraded UN membership on September 27.

Nabil Abu Rudeina, spokesman for Palestinian president Mahmud Abbas, said the date would be decided next week when Abbas meets the Arab League in Cairo.

"The president will have Palestinian, Arab and international consultations to set a date for the UN bid to present the request for non-member state status for Palestine," he said.

"After the Tehran summit, the president will go to Cairo to attend the Arab League follow-up committee meeting on September 5 and 6 which will set a date for the Palestinian bid seeking a status upgrade to non-member state."

Abbas was Thursday at a Non-Aligned Movement summit in Tehran where members are expected to vote on a political declaration endorsing Palestinian plans for upgrading their status from observer entity to a non-member observer state.

Last September, Abbas made a high-profile effort to obtain full member status for Palestine at the UN, but the request was never put to a vote in the Security Council where the United States had pledged to veto it.

The outcome of the NAM summit would have a "big effect" on Palestinian plans, Abu Rudeina said.

"The decisions taken at the NAM summit will have a big effect on the bid to seek non-member UN status for Palestine," he said, without explaining further.

On August 4, Palestinian foreign minister Riyad al-Malki had said Abbas would make the upgrade request on September 27 during the UN General Assembly.

"In the upcoming session of the General Assembly next month, President Abbas will speak about this on the 27th. Palestine will apply immediately to the UN, and the head of the General Assembly will be informed that Palestine wants to obtain non-member status," he told reporters.

"After that, we will begin communicating with all components of the General Assembly to talk about the appropriate date" for a vote on the issue.

Nimr Hammad, political adviser to Abbas said the UN upgrade request would definitely go ahead, but confirmed the date would only be set "in the upcoming weeks."

"The decision to go to the UN has been made by the Palestinian leadership and is no longer up for discussion. The date will be set in the upcoming weeks based on whatever serves Palestinian interests," he said.

"We want to ensure the largest international support for the decision and also ensure the voting would be in favour."

Several weeks ago, a senior official from the Palestine Liberation Organisation said Washington was pressuring the Palestinian leadership to delay its upgrade plans until after the US elections in November.

Palestinian negotiator Saeb Erakat also confirmed there was no date set for the application, but said the Palestinians would submit a draft resolution to the General Assembly which was likely to win support from "more than half" of the 193 member states.

"More than two-thirds of the General Assembly states already recognise us officially as the state of Palestine, and if the vote succeeds, Palestine will officially become a non-member state at the UN," he said.

"According to international law, we will be classified as a state recognised by the United Nations, but not a (full) member state as that requires a Security Council resolution."