Hamas on Monday shrugged off calls for reconciliation with Fatah, saying its secular rival must prove its seriousness by freeing prisoners.

"These declarations lack seriousness and credibility, they make no sense in light of the continued arrests and torture [of Hamas members] in Fatah prisons in the West Bank," said Hamas spokesman Sami Abu Zuhri, in response to an appeal by Fatah for the two factions to start talking.

"The only real way towards reconciliation is to stop the arrests, free the detainees and allow the movement's charities to start helping the Palestinian people again," he told AFP.

Hamas and Fatah are bitter opponents which have carried out periodic arrests of each other's members, often holding detainees without charge or trial and routinely trading allegations of prisoner abuse.

"The formation of a national unity government can only be achieved in the context of an all-encompassing national solution and not a partial one," he said, referring to calls for the establishment of a coalition which would rule until parliamentary elections can be held at some point before September.

Senior Hamas leader Ismail Radwan said the group was looking at a new interpretation of reconciliation -- one which would ensure a partnership with all the political factions.

"Hamas is involved in talks with the national factions to build a vision of national reconciliation on a new basis of preserving the national constants, far from the meaningless concessions and pressure from the American administration and the Zionist enemy," he said in a statement.

Their comments were made a day after a senior Fatah member called for the two movements to reconcile their differences.

"In the national interest, the Fatah movement underlines the need to respond to the demands of the Palestinian people to put an end to the division with a view to ending the occupation," said Azzam Al-Ahmad.

"We are ready to meet the Hamas leadership so that the Egyptian document can be signed," he added, referring to a Cairo-brokered deal which was endorsed by Fatah but rejected by Hamas.

The rivalry between the factions, which dates back to the early 1990s, soured dramatically after Hamas won elections in 2006 and, a year later, seized control of Gaza after deadly street fighting with Fatah.

Since then, the Palestinian territories have been effectively split in two, with the Fatah-dominated Palestinian Authority confined to the West Bank.

Repeated attempts at getting the two parties to reconcile their differences have led nowhere, and the Egyptian regime of Hosni Mubarak, which played a key role in reconciliation efforts, is now firmly out of the picture.