The Palestinian Economic Council for Development and Reconstruction, a Palestinian Authority body that oversees the implementation of donor-financed projects, said the process would take "five years if Israel removed its blockade over Gaza entirely."
Since 2006, Gaza has been subject to a blockade that, among other things, prevents the entry of construction materials, which can be used by militants to build tunnels and fortifications.
According to a ceasefire recently signed in Cairo these restrictions should be eased, but no such materials have yet been let in through Gaza's border crossings with Israel.
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The coastal enclave, home to 1.8 million people and bordered by Israel and Egypt, was ravaged between July 8 and August 26 in its third war in six years.
The conflict cost the lives of more than 2,140 Gazans, destroyed thousands of homes, severely damaged the enclave's sole power plant and burnt dozens of factories.
But the 1.8 million-2.2 million tonnes of debris estimated to have resulted from the destruction of buildings could also be used to expand the territory into the sea, according to the report by 13 Palestinian experts.
A conference of international donors for the reconstruction of Gaza is set to take place later in the month in either Egypt or Norway.