The captain of a Gaza-bound Libyan aid ship on Tuesday rejected an Israeli demand that it change course and dock in Egypt, the mission organisers said.

An Israeli military spokeswoman confirmed that a "process of identification and communication" with the vessel, some 160 km from the Gaza coast, had begun but said the ship had not been boarded.

"The Israeli navy has launched preparations and activity to stop the Libyan ship," the spokeswoman said.

A charity foundation chaired by Libyan leader Muammar Gaddafi's son, Saif al-Islam Gaddafi, said in a statement an Israeli navy ship was near the Amalthea, which left Greece on Saturday.

In response to the Israeli order to head for the Egyptian port of El Arish, "the captain of the Libyan ship and the head of the foundation team on board reaffirmed that the ship's destination is Gaza and no other place," the charity said in a statement.

Israeli Foreign Minister Avigdor Lieberman said on Sunday that Israel would not allow the Moldovan-flagged Amalthea, renamed Hope, to reach the Gaza Strip, territory controlled by its Hamas Islamist enemy.

Enforcing its Gaza naval blockade, Israel triggered an international outcry after its commandos raided a Gaza-bound Turkish-flagged aid vessel on May 31 and killed nine Turks, straining relations with once-close Muslim ally Turkey.-Reuters