Nasser al-Qidwa, speaking on Monday, said Israel would retain control of the area in a number of ways.
"The Israelis are leaving the entire Gaza Strip, but Israel will maintain control of its air space, territorial waters and, partially, the crossing points," he said.
"Consequently, the movement of people and contact with the outside world will still be controlled by Israel," al-Qidwa added.
Freedom of movement
The departure of Israeli soldiers and the dismantling of illegal Jewish settlements, 38 years after soldiers first occupied Gaza, will not amount to a total end of the occupation, he said.
"There will be no quick or satisfying solution for the Palestinians on matters connected to going abroad or the link between the Gaza Strip and West Bank. That needs more struggle and work," he said.
Palestinians fear Israel will
tighten its grip on the West Bank
Al-Qidwa, a nephew of the late Palestinian leader Yasser Arafat, did not minimise the importance of the impending pullout, due to begin in nine days.
Jewish settlements would be out of Gaza "forever" and the pullout would deal "a heavy blow to settlements in general", he said.
Many Palestinians are wary that Israel will use the pullout to strengthen its hold over Jerusalem and the West Bank, home to the vast majority of the 245,000 settlers. Officials also remain sceptical about the extent of disengagement.
Speaking to Aljazeera, the Foreign Ministry Undersecretary, Abd Allah Abd Allah, said: "The legal status of Gaza is that it is under occupation since the occupation is free to return to Gaza whenever it chooses.
"They want to control the daily lives of the Palestinians in Gaza," he said.
"Israel's disengagement, the settlers' relocation, the road map and the Arab peace initiative were all designed to effect change in the status quo in the way of ending the occupation. But this is not the end of Palestinian struggle," Abd Allah said.
Al-Qidwa said Israel was refusing to remove the rubble of settler houses, which are to be bulldozed during the operation. "The question of the rubble is still a problem," he said.
"It is true that we are going to be in charge of daily life of citizens in the Gaza Strip to a large extent, but we will not have sovereignty, which comes in control of the air space, the borders and territorial waters," he added.