The ministry of agriculture in the deposed Hamas government also banned people from pulling water from wells in those lands or grazing for fear that some of the projectiles had contained "radiant, cancer-causing and poisonous materials."
"This makes the targeted places infected and pose a threat to the human and animals," the ministry said in a statement sent to the media.
During the three-week war, which ended in January, the ministry said the Israeli aircraft had also bombed its labs and another advanced laboratory in Gaza's Islamic University, "making us unable to do chemical analysis" to the soil.
"We have sent samples for check outside Gaza Strip and the ban on entering the infected areas will remain until we get the analytic results," the statement said.
On Thursday, Italian specialists said Gaza Strip's soil contains poisonous and cancer-causing materials due to weapons Israel used.
The weapons left traces that could not be seen neither by unaided eyes nor equipment in Gaza hospitals and it is difficult to recognize them, said Professor Paola Manduca, a geneticist from the University of Rome.
She made the remarks to a seminar in Gaza over a video conference link.
Editor: Fang Yang