Peace activists planning to land two boats on Gaza's shores are no better than "pirates" and will be turned back by the Israeli navy, officials have warned.

Israeli officials are thought to see the protesters' efforts as a dangerous precedent.

"From my point of view this is some kind of pirate ship," said Shlomo Dror, a defence ministry spokesman.

"You can demonstrate, that's OK with us. But you are not allowed to break international law."