A senior leader of the Islamic Resistance Movement (Hamas) said on Tuesday he is not optimistic that the upcoming round of inter-dialogue would succeed after President Abbas' decision to form a larger Palestinian government.

Rival leaders of both Fatah and Hamas movements are scheduled to hold another round of inter-reconciliation dialogue in Cairo on May 16 to end differences over forming a unity government that ends political rift between Gaza and West Bank.

However, President Abbas announced earlier that a new larger government headed by Salam Fayyad will be sworn in most probably on Tuesday evening, a move that would affect the results of Cairo dialogue.

"Hamas will go to the dialogue, will continue its efforts and will work on succeeding it, but at the same time we don't count so much on its success because there are no positive signs," said Mahmoud al-Zahar in Gaza.

Al-Zahar, who slammed President Abbas decision to form a larger Palestinian government headed by Fayyad, told reporters "We will go to the dialogue within the coming few days."

"This move is so bad, negative and illegal," al-Zahar said. "It is also a clear indication that Ramallah leadership is not interested to see the inter-reconciliation talks succeeding."

A pro-Fatah movement website had published the names of the new ministers in the larger Palestinian government headed by Prime Minister Fayyad. Sources said the new government will be sworn in within the coming few hours.

"We really reject this move because the position (of Fatah), during the past rounds of dialogues and negotiations were all an attempt to oust Hamas movement and attract all the Arab powers against the movement," said al-Zahar.

He added "in spite of President Abbas decision," we will go to the dialogue with opened hearts and goodwill in order to reach an agreement, and we will exert every single effort but not on the expense of our people's interests," he said.