The navy said the barrier, stretching 950m into the sea, is necessary because of the expected loss of surveillance systems in the planned pullout, military officials told an Israeli reporter in Gaza, requesting that their names not be used because the project is still being discussed.

The barrier's first 100m will consist of cement pilings buried into the sandy bottom, The Jerusalem Post newspaper reported on Friday.

The paper said the structure will extend another 800m in the form of a 1.8m-deep fence floating beneath the surface.

Palestinian chief negotiator Saeb Erekat, said: "Now they have land barriers and tomorrow sea barriers and the day after sky barriers and what else? Will they put a barrier around each Palestinian individual or house?"

Israel has already fenced-off Gaza, home to 1.3 million Palestinians, with all access restricted and controlled by Israeli occupation forces.

UN condemnation

Despite UN condemnation and an International Court of Justice ruling against Israel's 8m-high concrete West Bank barrier, Israel has continued fencing-off Palestinians into enclaves.

Signalling a major diplomatic victory for the Palestinians a year ago, a European-Union-backed resolution, pressing Israel to heed the World Court ruling and demolish the wall, was approved by a 150-6 vote with 10 abstentions.

"Now they have land barriers and tomorrow sea barriers and the day after sky barriers and what else? Will they put a barrier around each Palestinian individual or house?"

Saeb Erekat,
Palestinian chief negotiator

Among those who voted against Israel was its staunchest ally, the United States.

Israel has consistently said it would ignore the ruling on 9 July 2004 by the International Court of Justice at The Hague and continue construction on the 700km separation wall.

The court said Israel had to dismantle the parts of the controversial barrier that was built on Palestinian territory and pay the Palestinians reparations for damages.

Sea separation barrier

In his response to another Israeli separation barrier, Erekat said: "I hope the Israeli mentality of barriers will end.

"This is the wrong policy. This is political blindness. The answer to all these woes of security and so on, is a meaningful peace process, is building the bridges with the Palestinians, is ending the occupation."

Israeli military officials said construction of the new sea barrier will begin soon and that it will be a major project costing millions of dollars, though they did not say how much.

The barrier is not expected to be complete in time for Israel's planned withdrawal from Gaza, set to begin in mid-August.