A Lebanese aid ship aiming to reach Gaza in defiance of Israel will "probably be delayed," organisers said Saturday, on the eve of its planned departure, after Cyprus denied use of its waters and ports.

The Mariam, a Bolivian-flagged cargo ship renamed for the all-women aid operation, was to have set off from the northern Lebanese port of Tripoli on Sunday night, headed for Cyprus on the first leg of a crossing to Gaza.

But Rima Farah, spokeswoman for the group, told AFP the mission could not go ahead without the green light from the Cypriot authorities.

"We are continuing our contacts with countries such as Turkey and Greece for them to allow us to dock. Pending their reply, the project will probably be delayed," she conceded.

Farah said a new date would be announced once the organisers had the green light from a third country.

Israel came under international censure over its May 31 seizure of a six-ship aid fleet bound for the Hamas-ruled Gaza Strip when Israeli commandos shot dead nine Turkish activists in a clash on the lead boat.

On Friday, Israel said it could use force again to stop the new aid boat to Gaza, even as a Lebanese minister said Beirut refused to bow to warnings against authorising the mission to the blockaded Palestinian territory.

In a letter to UN chief Ban Ki-moon, Israel's UN Ambassador Gabriela Shalev said the stated intention of the Mariam was "to violate the existing naval blockade of Gaza."

Israel also had information that another vessel, the Naji al-Ali, plans to leave from Lebanon with the aim of violating the blockade, she said.

"Israel reserves its right under international law to use all necessary means to prevent these ships from violating the aforementioned naval blockade," Shalev warned.

She said such "confrontational actions by the organisers, as well as those that offer their consent, is deeply troubling," also charging that the organisers had suspected links to Lebanon's Shiite militant group Hezbollah.

But Lebanon's Transport Minister Ghazi Aridi said his country would "not respond to the wishes or requests" of Israel. "We will continue to exercise our sovereignty and make the decisions we find appropriate," he said.

The Mariam, renamed in honour of the Virgin Mary, plans to carry aid to Gaza in a bid to break Israel's four-year siege with more than 50 Lebanese and foreign women activists on board.

However, the Cyprus government has said it was keeping in place a ban on ships sailing from the island to the Gaza Strip.

The organisers of the Mariam are due to hold a news conference at 11:00 am local time (0800 GMT) on Sunday.

The Naji al-Ali, another Lebanese boat organised by journalists, has also announced it would sail to Gaza via Cyprus but has not yet received clearance from Lebanese authorities.