Facing considerable opposition, much of it from his own party, Sharon said several weeks ago that the evacuation of the 21 Jewish settlements in Gaza and four in the West Bank should be carried out simultaneously at the beginning of 2005.
Interviewed on Wednesday on Channel 10 TV, Sharon said: "I estimate now that the evacuation, which I believe will take about 12 weeks, will be very complex and very difficult, will be done in the summer. I can't give an exact date, but it must be done in the summer.
"All of this is very difficult. We're dealing with exceptional people, people who showed stamina and real heroism for years," he said, referring to the settlers.
Sharon faces opposition to his
Gaza pullout plan from settlers
Sharon lost his parliamentary majority over his "unilateral disengagement" plan because his traditional constituency comes from the settlers and their backers.
Pro-settler ministers quit his cabinet in protest.
Analysts say Sharon's government can survive until March, when the parliament must pass a budget.
If it can't get the spending plan approved, the government will fall and elections must be called.
Sharon's earlier, speeded-up timetable appeared to take into account that the Gaza pullout must be completed before the March date.
"I can't give an exact date, but it must be done in the summer"
Israeli prime minister
Also, the concept of completing the pullout in one stage instead of the three, as proposed initially, was seen as a way to limit opposition on the ground.
The 12-week format effectively reinstates the evacuation in stages.
Critics of the stages formula warned that settlers opposed to the plan could move from settlement to settlement, mounting resistance to soldiers and police trying to evacuate the enclaves.
Sharon has said he will reinforce his coalition and restore its majority, but his own Likud Party blocked the addition of the moderate Labour Party to his team.
Labour, Likud's traditional rival, strongly backs the Gaza pullout.