A planned visit by the Qatari emir to Gaza shows he is backing the strip's Islamist Hamas rulers over the Western-backed Palestinian Authority of president Mahmud Abbas, an Israeli official said Monday.

Sheikh Hamad bin Khalifa al-Thani is due to arrive on Tuesday in connection with a major Qatari investment project to rebuild Gaza, in what will be the first time a head of state has visited the enclave since Hamas took over in 2007, ousting forces loyal to Abbas.

"We find it weird that the emir doesn't support all of the Palestinians but sides with Hamas over the Palestinian Authority (in the West Bank) which he has never visited," Israeli foreign ministry spokesman Yigal Palmor told AFP.

"The emir has chosen his camp and it is not good," he said.

Qatar has tried to mediate in a process of national reconciliation between Hamas and Abbas's rival Fatah faction, and in February hosted talks between the Palestinian leader and his Hamas counterpart, Khaled Meshaal, who has recently shifted his political base from Damascus to Doha.

So far, attempts to reconcile the two factions have failed.

The emir is expected to arrive in Gaza at 11:00 am (0900 GMT) on Tuesday via the Rafah border crossing with Egypt.

Last month, Mohammed al-Emadi, Qatar's envoy to Gaza, said Doha was to invest $254 million (195 million euros) in rebuilding Gaza in a project which would involve the construction of roads, housing and infrastructure, as well as agricultural development.