The Palestinian Hamas movement has urged Arab countries to boycott a US-sponsored Middle East peace conference planned for next month.
Haniya was sacked after Hamas seized control of Gaza in June
Dismissed prime minister Ismail Haniya said in a magazine interview he had no hope of any positive results emerging from the summit.
He called on Egypt and Saudi Arabia, in particular, not to join the event.
Palestinian President Mahmoud Abbas has said 36 countries, including 12 Arab states, could attend November's summit.
In his interview with Palestine magazine, Mr Haniya said: "We do not put the slightest hope in this conference."
He also spoke out against "any normalisation" of relations with Israel.
His comments came as Israeli and Palestinian negotiators prepared to begin work on Monday to agree a joint declaration ahead of the planned summit.
US Secretary of State Condoleezza Rice is due to visit the region next week to add her weight to the preparations.
The US has said the conference must address substantive issues and advance the cause of a Palestinian state.
Hamas seized power in the Gaza Strip in June, ousting Fatah forces loyal to the Mr Abbas, who responded by sacking Mr Haniya.
The confrontation has left the Palestinian territories divided, as Hamas remains in charge in Gaza and Fatah retains control at its power base in the Israeli-occupied West Bank.
Hamas is designated a terrorist organisation by the US, the European Union and Israel.