Fatah leader Mahmoud Abbas (right) and Hamas leader Khaled Meshaal (left) in row over unity prime minister [Getty]

A planned announcement of a new Palestinian unity government has been delayed after the Fatah and Hamas movements failed to agree on a prime minister.

The announcement was planned for Tuesday, but Fatah officials told the Reuters news agency that talks between Palestinian Authority President Mahmoud Abbas, who heads Fatah, and Hamas chief Khaled Meshaal, had been postponed.

The unity deal was reached after both groups agreed to a reconciliation deal in April, when the rival factions agreed to form an administration of ministers without party affiliations, to prepare for general elections within a year.

Fatah, led by Western-backed Abbas, nominated Salam Fayyad, a former World Bank economist who currently heads the Palestinian government in the West Bank, to the post.

Hamas, the group which maintains power in the Gaza Strip since taking control from Fatah in 2007, has rejected Fayyad, accusing him of co-operating with Israel's blockade on Gaza.

"We asked our brothers and the Egyptian leadership to postpone the meeting for several days," said Azzam al-Ahmed, head of the Fatah delegation to unity talks in Cairo, citing Abbas's busy schedule. 

"We will call them in a few days to set a date for a new meeting, and we hope the next session will be successful," he told Reuters.

'Serious implications'

Other Fatah officials, who asked not be identified because of the sensitivity of the issue, attributed the delay to the dispute over appointing Fayyad.

Hamas spokesperson Taher Al-Nono confirmed that Fatah asked for a delay.

"We are ready to meet once they are," Al-Nono told Reuters.

A statement issued earlier from the office of Ismail Haniyeh, the head of Hamas' administration in Gaza, said: "The meeting may be postponed and this will have serious implications for the discussions on forming the government."

Last week, Palestinian officials said Abbas and Meshaal would meet in Cairo on Tuesday to unveil the new government.

Fayyad supporters say his standing abroad was an asset for Palestinians in ensuring the continued flow of international aid and in pursuing a bid for UN recognition of Palestinian statehood, expected in September.

Israel has said the reconciliation accord, brokered in secrecy by Egypt, would not secure peace and it urged Abbas to continue to shun Hamas.