Shaul Mofaz told Israel Army Radio on Tuesday he was committed to the Gaza withdrawal under any circumstance.
"The disengagement will not be cancelled," he said.
His comments come after Prime Minister Ariel Sharon officially announced a postponement of the pullout for religious reasons and Foreign Minister Silvan Shalom suggested cancelling the withdrawal altogether.
Shalom said on Monday Israel should consider calling off the pullout if Palestinian resistance movement Hamas consolidates its support in municipal elections.
The foreign minister added that in the event of a strong Hamas showing in July elections, Israel would be handing territory to a "militant group".
Asked to comment, Mofaz said: "I don't know what the [election] results will be in Gaza ... yes, Hamas has been strengthened ... but I think we need to make supreme efforts to carry out the disengagement. At the end of the day, it's good for Israel."
Point of agreement
But Foreign Ministry spokesman Mark Regev played down any split between the foreign and defence ministries.
He told Aljazeera.net on Tuesday that, while he could not comment on any pullout cancellation, it was a foregone conclusion that Mofaz and other cabinet members would at least agree to a three week delay.
Shalom has always expressed his
concerns over the Gaza pullout
"Naturally, this is a decision that has to be ratified in the coming cabinet meeting, but it is a foregone conclusion - the pullout has been delayed. It's a fact."
Aljazeera.net's requests for further information from Israel's Ministry of Defence were not immediately answered.
But, speaking to Aljazeera, chief Palestinian negotiator Saib Uraiqat said he believed Israel was simply exploiting an opportunity to stay away from bilateral negotiations.
"While Israel continues its policies of settlement, land confiscation and house demolition - there are no negotiations ... Sharon listens to rabbis and then postpones the implementation of the plan," Uraiqat said.
"Israel only wants us (the Palestinian Authority) to receive its orders", he added, describing Shalom's announcements as "impudent and inappropriate".
Uraiqat also stated his belief that Shalom wanted Palestinians to vote for Hamas, as he could use it as a pretext to avoid any possibility for negotiations in the future.