A settler activist heading a group opposed to withdrawal from the Gaza Strip has said thousands of troops will try to sabotage the move.
Some soldiers are prepared to face jail rather than remove settlers
Noam Livnat told the BBC News website up to 20,000 soldiers had signed a petition vowing to disobey orders to remove Jewish settlers.
The Israeli army says the claim is exaggerated.
The withdrawal from Gaza and four small West Bank settlements is due to start in the middle of August.
Israel Defense Force spokesman Captain Ishai David told the BBC News website that dissent was expected but the number of soldiers involved would be small.
"We already have proof that IDF soldiers will not disrupt the mission. We believe the way the soldiers dealt with the pro-settler demonstrations at Kfar Maimon shows how the soldiers will behave.
"Our soldiers performed superbly in blocking the protesters from getting to Gush Katif."
Thousands of Israeli protesters were prevented from entering Gaza to attempt to disrupt the disengagement plan.
In recent weeks, a growing number of soldiers have faced disciplinary action, saying they will refuse to follow orders to remove settlers from Gaza.
Mr Livnat - the brother of Israeli Education Minister Limor Livnat - said soldiers would try to thwart the plan by not following orders properly.
"I expect thousands of soldiers to do their work inappropriately," he said.
"When the time comes, soldiers will go on the mission but they won't do it right, they will fail to do what they are supposed to.
"It is not a political game for us, it is not that we want to show Ariel Sharon that we can object - what we want to do is simply to stop this, to prevent this terrible mistake from happening," he said.
Mr Livnat said twice as many soldiers and reservists had signed the petition in the period since February, when it was first made public.
The document reads: "We, the undersigned, are citizens of the State of Israel and serve in the army with pride while acknowledging our obligation and privilege to protect the Israeli people during time of war.
"We identify with rabbis who view the disengagement plan as a national disaster and we declare that we will not lend a hand to the plan."
Mr Livnat, who heads the Defensive Shield movement, said there was little appetite for the plan among the rank and file.
"If you go to soldiers today and hear them talking, you can see they do not support the plan.
"Even those who are left-wing, even if they are for this plan they do not feel right about this, of being a policeman and throwing a family out of their home. They say it is not what they came to the army to do.
"From every angle - religiously, logically, security, politically and humanitarian - there is not one thing you can say for this plan," he said.