The comment by Major-General Alain Pellegrini, the UN force commander in Lebanon, came after he met with Israeli and Lebanese officers at the border to discuss the continued withdrawal of Israeli troops.
He said: "It is my belief that with the necessary co-operation by both parties we should see the [Israeli army] leave south Lebanon by the end of this month."
Israeli forces have gradually been pulling out of Lebanese territory after their 34-day war with Hezbollah but small forces remain on the Lebanese side of the border.
However, Israel's Channel One television said that disagreements at the meeting over the disarming of Hezbollah in southern Lebanon could delay the withdrawal beyond the weekend.
Alexander Ivanko, a spokesman for the UN force, said that the peacekeepers had not been informed of any delay in the pull-out.
He said: "We have not been informed about any delays or timetables but it has been made clear by the [UN] force commander that he expects the process to be finalised by the end of the month."
Rules of engagement
Amir Peretz, the Israeli defence minister, said earlier on Tuesday that Israel hoped to complete its withdrawal soon but that this would depend on agreement being reached with the UN force on rules of engagement.
He said: "I hope very much that during the coming week, at the most a few more days, we will complete the withdrawal.
"There are arrangements, negotiations [and] deliberations which we intend to complete in order to set the rules - what is permitted and what is forbidden."
Mark Regev, the Israeli foreign ministry spokesman, said that Israel would withdraw once it was convinced that the terms of UN resolution 1701 that ended the war on August 14 would be observed.
He said: "We have no desire or intention to prolong our stay in Lebanon, and the minute it is understood that the other relevant parts of 1701 will also be fulfilled, then of course Israel will be ready to pull out.
"Resolution 1701 specifically calls for a total arms embargo to prevent arms reaching Hezbollah [and] the total elimination of an armed Hezbollah presence south of the Litani river, and we're hopeful that the Lebanese government and the international forces will be acting to provide those conditions to make the Israeli withdrawal expeditious."
UN commanders have said that they will not disarm Hezbollah or open fire on Hezbollah fighters and Israel feels that the Lebanese government has given mixed signals on whether it is prepared to confront Hezbollah, which has two members in the Lebanese cabinet.