A ship with supplies for Gaza will dock at el-Arish in Egypt, officials say, after Israeli pressure to stop the vessel breaking its Gaza blockade.
The Moldovan-flagged ship chartered by a charity run by the son of Libyan leader Col Muammar Gaddafi, left a Greek port on Saturday.
Israel asked for help from the UN, and had talks with Greece and Moldova. But organisers insist they will go to Gaza.
An Israeli raid on a Gaza-bound ship in May killed nine Turkish activists.
Israel insisted its troops were defending themselves but the raid sparked international condemnation.
Israel recently eased its blockade, allowing in almost all consumer goods but maintaining a "blacklist" of some items.
Israel says its blockade of the Palestinian territory is needed to prevent the supply of weapons to the Hamas militant group which controls Gaza.
The Amalthea, renamed Hope for the mission, set off from the Greek port of Lavrio, loaded with about 2,000 tonnes of food, cooking oil, medicines and pre-fabricated houses.
It has been chartered by the Gaddafi International Charity and Development Foundation. Its chairman is Saif al-Islam Gaddafi.
The organisation said the 92m (302ft) vessel would also carry "a number of supporters who are keen on expressing solidarity with the Palestinian people".
The BBC's Malcolm Brabant in Lavrio says the Libyans clearly believe the time is right to test Israel's resolve to maintain the naval blockade.
Israel carried out intense diplomatic activity to prevent the Amalthea reaching Gaza.
A foreign ministry statement said that Foreign Minister Avigdor Lieberman had spoken with his Greek and Moldovan counterparts on the issue.
The statement said: "The foreign ministry believes that due to these talks, the ship will not reach Gaza."
And Libya has now told the Greek government that the ship will now dock in Egypt's el-Arish on the coast of the Sinai Peninsula.
"We confirmed their destination in talks with the Libyan ambassador and the ship's agent," foreign ministry spokesman Grigoris Delavekouras told Associated Press news agency.
Israel also lobbied the UN to take action.
Israel's UN Ambassador Gabriela Shalev said in a letter: "Israel calls upon the international community to exert its influence on the government of Libya to demonstrate responsibility and prevent the ship from departing to the Gaza Strip."
Ms Shalev also warned: "Israel reserves the right under international law to prevent this ship from violating the existing naval blockade on the Gaza Strip."
She said the motives of the operators were "questionable and provocative".
However, the director of the Libyan charity told the BBC the vessel was heading for Gaza.
"We have not cut deals with anyone," Youssef Sawwan told the BBC Arabic service.
"We are heading to Gaza for purely humanitarian reasons, we are not out to provoke anyone or to seek media attention," Mr Sawwan said.