An Israeli cabinet minister's Twitter account was hacked Wednesday by a pro-Palestinian outfit which posted messages in his name calling Prime Minister Benjamin Netanyahu a "murdering psychopath".

The string of tweets on the page belonging to vice prime minister Silvan Shalom included messages reading: "Free Palestine! End the occupation! Stop the murder of Palestinians now!"

Another said: "Benjamin Netanyahu is a Zionist murdering psychopath" while others called for a worldwide boycott of Israeli products.

The page was down for several hours.

An outfit calling itself ZCompanyHackingCrew that has also claimed attacks on the websites of NATO and the British defence ministry claimed responsibility for hacking Shalom's Twitter and other social media accounts.

"@SilvanShalom WAS The Official Twitter Page of The Vice Prime Minister of Israel. Hacked by @Z_H_C_," the activists announced early on Wednesday.

"#silvanshalom was the guy who said to blow up #gaza two days ago. Taste it now!" it said in another message.

Shalom's Facebook account was also briefly down on Wednesday afternoon and his Blogspot page featured a video of militants fighting Israeli troops.

The Israeli government on Sunday admitted it had been hit by 44 million hacking attempts by pro-Palestinian activists protesting Israel's Gaza air campaign, which began on November 14.

The prominent Internet activist group Anonymous has earlier claimed to have corrupted hundreds of private and public Israeli accounts since the start of the offensive.

But ZCompanyHackingCrew insisted that it was operating independently of Anonymous or the Islamist Hamas movement that runs Gaza.

"we are not hamas we are not anonymous," the group tweeted.