Israel is to allow limited quantities of building materials, for use by the private sector, into the blockaded Gaza Strip starting from Sunday, a Palestinian official said.

After "efforts exerted by the Palestinian Authority, Israel has agreed for the first time in six years for building materials such as cement, iron and gravel to be brought into Gaza from Sunday" through the Kerem Shalom goods crossing, said Raed Fattouh, PA official in charge of Gaza supplies.

An Israeli official, who asked not to be named, confirmed the move, telling AFP it was a bid to "strengthen the economy and support [Palestinian president Mahmud] Abbas."

The quantities allowed in per day will be 1,600 tonnes of gravel, 800 tonnes of cement and 400 tonnes of iron, Fattouh said.

Israel has also begun constructing a water line that will double the amount of water supplied by the Jewish state to Gaza from five million to ten million cubic metres (353 million cubic feet) a year, the Israeli official noted.

A Hamas government official told AFP allowing building materials into Gaza was a positive development, but insufficient.

"It's a positive step, but Gaza needs 6,000 tonnes of gravel, 4,000 of cement and 1,500 of iron per day," deputy-economy minister Hatem Oweida said.

Middle East Quartet representative Tony Blair praised "the Israeli government's decision to approve a series of easing measures for the West Bank and Gaza."

"This is an important step in building a more positive environment for diplomatic negotiations," he said in a statement.

Last week, Israel approved the allocation of 5,000 work permits for Palestinians from the West Bank. According to the Israeli official, this brings the number of Palestinians working in Israel and West Bank settlements to 100,000, of them some 30,000 without permits.

Building materials have long been smuggled from Egypt into Gaza through tunnels underneath the border town of Rafah, but the Egyptian army recently destroyed many of those after ousting president Mohamed Morsi of the Muslim Brotherhood, a Hamas ally.

Israel first imposed its land, sea and air blockade on Gaza in 2006 after militants there seized an Israeli soldier.

It was further tightened in mid-2007 when the Islamist Hamas movement took control of Gaza.

The Jewish state eased the blockade slightly following an international outcry after Israel's botched raid on a Turkish Gaza-bound flotilla in 2010 to allow food and building materials for internationally funded projects.

Israel said it feared construction materials could be used by Hamas in their attacks on the Jewish state.

The blockade was further eased after an eight-day confrontation between Israeli and Hamas militants in November 2012, following which Israel has allowed 20 trucks of gravel in each day.