This comes although members of his own party and government were battling the pullout plan.
"The referendum is one of the options being envisaged, but there is also the option of early elections and the formation of a new government," the official told AFP on condition of anonymity.
"All these options are being studied at the moment."
Sharon dropped a political bombshell on Monday by stating that "in the future there will be no Jews in Gaza."
The evacuation of the Gaza settlements forms part of a larger "disengagement plan" which the government has said it will start implementing in the summer if no progress is made in the peace process with the Palestinians.
Although Sharon was widely reported to have told his aides that he would call elections in June or July if he is not given parliamentary backing for his plan, it was the first time that the option of a referendum had been confirmed.
A poll published in Tuesday's Yediot Aharonot daily showed that 59% of Israelis backed his move against 37% who were opposed.
Sharon is expected to travel to Washington later this month to brief US President George Bush on his proposals, a move right-wing members of his coalition cabinet have warned will precipitate their resignations.
"I hope Sharon is not bluffing us and bypassing the implementation of the roadmap"
National security advisor to Palestinian President Yasir Arafat
The traditionally hawkish premier has said he is determined to push through with the uprooting of the 7500 Jewish settlers living in Gaza. His chief of staff, Dov Weisglass, is expected to travel to the United States in the next few days to lay the groundwork for a visit.
Yediot said the main opposition Labor party would most likely join a national unity government after a walkout by both the National Religious Party (NRP) and National Union Party (NUP).
Labor party leader Shimon Peres has already pledged parliamentary backing for Sharon's plans but has still to declare whether he would join a national unity government.
Peres accused Sharon of "running
away" with his plan for Gaza
Transport Minister Avigdor Lieberman, leader of the NUP, was confident that Sharon would not get cabinet approval for his plan.
"There is a reasonable chance that we will succeed in mobilising a majority in the cabinet against this plan of Sharon's," he told the radio.
Likud deputies were also gathering signatures for a petition warning Sharon against making any decisions regarding Gaza without first consulting the party.
Palestinian officials have voiced scepticism about whether Sharon will actually see through the evacuations, but prime minister Ahmad Quraya said he "welcomed any process that leads to a withdrawal from occupied Palestinian territory".
Palestinian president Yasir Arafat's national security advisor, Jibril al-Rajub, cautioned: "I hope Sharon is not bluffing us and bypassing the implementation of the roadmap."
Both sides have said for months that they are willing to hold talks but the two premiers have yet to meet, nearly five months after the resignation of Quraya's predecessor, Mahmud Abbas.
Palestinian negotiator Uraiqat was
to meet his Israeli counterpart
Their respective chiefs of staff were due to meet in Jerusalem on Wednesday in yet another bid to line up a summit.
Weisglass and Quraya's top aide, Hassan Abu Libdeh, were to be joined by a senior advisor to Sharon, Shalom Tourdjman, and chief Palestinian negotiator Saib Uraiqat.
Israeli Prime Minister Ariel Sharon's bureau chief was to meet with his counterpart from Palestinian premier Ahmad Quraya's offices on Wednesday to prepare for a long-awaited summit, officials said.