Hamas "will never recognise Israel," Gaza prime minister Ismail Haniya said Saturday in a speech in Iran that is likely to complicate Palestinian efforts to form a unity government in the teeth of opposition from the Jewish state.

"They want us to recognise the Israeli occupation and cease resistance but, as the representative of the Palestinan people and in the name of all the world's freedom seekers, I am announcing from Azadi Square in Tehran that we will never recognise Israel," Haniya said.

"The resistance will continue until all Palestinian land, including Al-Quds (Jerusalem), has been liberated and all the refugees have returned," he said.

Haniya's reiteration of Hamas's long-held stance was made on the occasion of Iran's commemoration of its 1979 Islamic revolution. The Gaza leader spoke to an estimated crowd of 30,000 from a stage alongside Iranian President Mahmoud Ahmadinejad.

Israel rejects efforts by Hamas to link up with Fatah, the secular faction of Palestinian president Mahmud Abbas that runs the West Bank, to form a unity government. It views Hamas as a terrorist organisation and Iran as its sponsor and weapon supplier.

Israeli Foreign Minister Avigdor Lieberman told UN envoys on Thursday that a Hamas-Fatah accord signed this week to partner in the new government "does not contribute to the advancement of peace negotiations or the well-being of the Palestinian people."

The so-called Quartet of diplomatic players in the Middle East peace process -- the European Union, Russia, the United Nations and the United States -- has long demanded that any Palestinian government including Hamas must meet certain conditions to join negotiations.

Those are the renunciation of violence and the recognition of Israel and of past agreements with the Jewish state.

Direct peace negotiations between Israel and the Palestinians have been frozen since September 2010. The Palestinians have demanded that Israel halt settlement construction in the occupied West Bank. Israel rejects any conditions for talks to settle the Middle East conflict.