The minister, Gideon Ezra, was deputy chief of the Shabak security service before entering politics.
Shabak head Avi Diechter, Sunday told the cabinet Jewish extremists' opposition to the planned pullback is "very worrying."
Israel is heading for a "difficult and complex period," he said.
Recalling the 1995 assassination of Prime Minister Yitzhak Rabin by a right wing Jew, Ezra said, "In light of the unfortunate experience we have gained in this matter, it is worthwhile [to act] one hour in advance, and (even) if there is some exaggeration in this matter ... it is worthwhile that the people know, be cautious, and alert others."
Someone might "interpret incorrectly the comments of rabbis and others concerning resistance (to the withdrawal). These people must be located ahead of time," the Ha'aretz news service reported.