A bizarre video where a gay activist claims he was prevented from taking part in the upcoming Gaza-bound flotilla because of his sexual orientation has been exposed as an Israeli hoax.

It appears to be the latest in a dirty-tricks campaign that includes sabotage and legal challenges orchestrated by groups seeking to derail and discredit efforts by activists to sail into Gaza's waters to challenge Israel's blockade of the Palestinian territory.

In the three-minute clip originally posted by an Israeli Government employee, a man calling himself Marc Pax says he has a "heartbreaking" story to share about his efforts to join the Freedom Flotilla II, a 10-ship convoy of about 350 activists, who include New Zealanders, European politicians, writers and an 86-year-old Holocaust survivor.

He said that his vision of activists as "a cross between Che Guevara and Mother Teresa in a keffiyeh [Arab headscarf]" were quickly disabused when his request to participate was rebuffed because he was gay.

He goes on to identify groups such as Viva Palestina and IHH, the Turkish organisers of last year's flotilla, as sympathetic to Hamas, the Gaza overlords which he blasts as a homophobic group that runs roughshod over basic human rights.

The video was released as activists prepare to commemorate the events of a year ago when Israeli Marines mounted a bungled raid on the Gaza-bound sea convoy, killing nine Turkish activists.

But it appears that wildcat groups, possibly with Israel's official backing, are also trying to stop the flotilla. Bloggers first became suspicious of the supposedly amateur video by its slick production and heavy promotion by Israeli Government bodies on Facebook and Twitter. Within hours, they had exposed Marc Pax as one Omer Gershon, an Israeli actor living in Tel Aviv.

The video was originally posted on Twitter by Guy Seeman, an intern working in Prime Minister Benjamin Netanyahu's office. Israel's press office and the Foreign Ministry both linked to it following his post.

Once the video was revealed as a hoax, the press office apologised, saying it had been "duped", and the Foreign Ministry removed the link from its Twitter feed.

The flotilla had been expected to set sail early this week, but boats moored at a Greek port have been hit by a series of mishaps. Activists on a boat taking Greek, Swedish and Norwegian passengers said their propeller shaft had been sabotaged.

An Israeli legal group called Shurat Hadin has also delayed the departure of at least one ship, the Audacity of Hope, by informing the Greek authorities that it was not seaworthy, obliging authorities to inspect it. Activists claimed it had earlier been cleared to sail.

Two French ships have already left a Corsican port, and an Irish ship is also en route to the Mediterranean. Activists in Greece say they hope to leave this week.

- Independent