Israeli Prime Minister Benjamin Netanyahu ordered authorities on Wednesday to block entry of pro-Palestinian activists planning to travel to Tel Aviv over the weekend in a protest "fly-in".

Netanyahu ordered the internal security minister and the immigration authority to "act with determination, while trying to avoid unnecessary friction" with anyone taking part in what he termed a provocation, a statement from his office said.

Pro-Palestinian websites have called in recent weeks on activists to fly to Israel on July 8 to protest against its policy toward Palestinians.

They say Israel routinely turns away activists in pro-Palestinian movements bound for the occupied West Bank, a policy they condemn as illegal.

"Every country has the right to prevent entry of disrupters and provocateurs at its borders," Netanyahu said at Tel Aviv's Ben-Gurion airport, where he discussed the "fly-in" with officials before embarking on a visit to Romania.

Michael Rabb, an American pro-Palestinian activist, told Israel Army Radio he expected 500 activists to arrive at Ben- Gurion airport on Friday and "announce openly and honestly that we're flying in to Palestine to visit our friends".

Bentzi Saar, a police commander, told the radio that Israel believed hundreds of activists would board some 50 flights from Europe between Thursday night and Friday.

"Our intelligence says some of these people want to cause confrontation...we will not allow any provocation or disruption," he said adding that Israel regularly bars the entry of anyone tagged by security as a potential threat to public order.

Police spokesman Micky Rosenfeld told Reuters hundreds of policemen were deployed in around the airport to ensure no disturbance is caused at the airport.

The planned fly-in follows unsuccessful attempts by a flotilla of pro-Palestinian activists to set sail for the Gaza Strip and challenge an Israeli naval blockade of the enclave run by Hamas Islamists. The convoy is docked in Greece, which has prevented it from leaving its waters.

Pro-Palestinian international activists regularly join locals in demonstrations against Israel in the occupied West Bank, which often end in violence.