Hamas lawmakers launched an unprecedented campaign on Sunday against the Western-backed Palestinian Prime Minister Salam Fayyad over his plan to expand a government excluding the Islamic Hamas movement.

"Fayyad is a Zionist phenomenon that should be omitted from the Palestinian dictionary," said a statement issued by Hamas lawmakers who are now jailed by Israel.

It was the bitterest attack against Fayyad since President Mahmoud Abbas asked him to form a government based in the West Bank in June 2007 following Hamas' violent takeover of the Gaza Strip.

Fayyad has been asked again to reshuffle and expand his cabinet ruling out Hamas, which won the parliamentary elections in 2006, from the new government.

"The role of Fayyad is dirty, since he makes conspiracies against our people and meets our enemy's desire of cracking down on the resistance," the jailed Hamas legislators said in the statement.

But the statement was not welcomed by Hamas officials who are based in the West Bank.

"Despite our big difference with Fayyad and our demand that his government be put before the parliament, the language in this statement is not ours," said Mahmoud al-Rumhi, secretary-general of the Hamas-dominated Palestinian Legislative Council (PLC).

Fayyad's new government is expected to be sworn in soon despite ongoing unity and reconciliation talks between rival Hamas and Fatah party loyal to Abbas in Egypt.

Palestinian National Authority officials have said once the two movements agree on ending schism and form a unity government, Fayyad's administration will quit.