The Israeli army said the missile strikes, which continued into the early hours of Monday, targeted uninhabitated areas in northern Gaza.
The heavy night raids came in the aftermath of a rocket attack, claimed by Islamic Jihad, on the outskirts of the southern Israeli city of Ashkelon in which no one was hurt.
The Palestinian Centre for Human Rights (PCHR) says three of the Israeli missiles hit important pieces of infrastructure, including a road in Bait Lahiya, damaging it and a number of houses.
Another missile destroyed the road leading to Umm al-Nasr village, 100m from the Balsam hospital, damaging several of the building's windows, the PCHR said in a statement released on Monday.
Other missiles left craters that made roads linking the towns of Bait Hanun and Bait Lahiya with Gaza City impassable.
The raids triggered a blackout in a large swathe of northern Gaza.
On Sunday morning, Israeli war planes launched six mock raids on the same areas, for the third day in a row. The sonic booms shake buildings and break windows.
Agricultural areas to the east of the southern Gaza town of Khan Yunus were also targeted, said the PCHR.
"PCHR is concerned that more casualties may occur among Palestinian civilians in light of the green light given by the Israeli government to the IOF to commit more extra-judicial executions and attack Palestinian areas in the Gaza Strip"
Palestinian Centre for Human Rights statement
The rights group says the attacks "further prove that the Israeli disengagement plan was a form of IOF [Israeli occupation forces] redeployment rather than an end to occupation as the Israeli occupation is still effective both physically and legally".
"PCHR is concerned that more casualties may occur among Palestinian civilians in light of the green light given by the Israeli government to the IOF to commit more extra-judicial executions and attack Palestinian areas in the Gaza Strip."
The PCHR, based in Gaza City, is an independent Palestinian human rights organisation that enjoys consultative status with the Economic and Social Council of the United Nations (ECOSOC). It was established in 1995 by a group of Palestinian lawyers and human rights activists.