Tens of thousands of ultra-Orthodox men attended a huge rally in New York's Citi Fields to discuss the dangers of the internet.

The event took place at the Citi Field Stadium in Queens, New York, known as the home baseball park of the city's Mets.

It was organised by an ultra-Orthodox group called Ichud HaKehillos LeTohar HaMachane, or Union of Communities for Purity of the Camp.

Tickets organisers were only allowed to sell places to men, in line with the ultra-Orthodox tradition of keeping the sexes separate.

Viewing parties of the events had been organised in nearby neighbourhoods, so women could also be kept informed of the rally's discussions and workshops.

The event focused on the internet and its impact on ultra-orthodox followers as well as on the 'moral dangers' attached to the uncensored web, such as access to pornography and other explicit content.

One speaker compared the threat of the internet to the dangers that Zionism and the European Enlightenment posed in the past to traditional Jewish life.

Others discussed the web's influence on yeshiva students, warning that it tends to distract them.

Several rabbis said Jewish law forbids Jews from using the internet without a filter system that blocks inappropriate sites.

"The internet even with a filter is a minefield of immorality," Jewish Telegraph Agency quoted Rabbi Ephraim Wachsman as saying.

"This issue is the test of the generation. Your strength at this gathering will determine what Judaism will look like a few years from now."

A group of about 50 protesters gathered near the stadium to protest against the event, but a spokesman for the rally defended the move.

"No one here is a Luddite who denies the manifold benefits that technology has brought to mankind as a whole," Haaretz quoted Eytan Kobre, spokesman for the event, as saying.

"But at a certain point, a mature, thinking individual stops and says, 'I've got to make a... cost-benefit analysis... [of] what ways it is enriching my life, [and] in what ways it is undermining it.'"

The event opened with a Kosher Tech Expo featuring web filtering technology, but failed to convince the most conservative factions.

"The purpose of the [gathering] is for people to realise how terrible the internet is and, of course, the best thing for every [good Jew] is not to allow it in his home at all," Rabbi Matisyahu Salomon, one of the lead sponsors of the rally, told the Brooklyn Orthodox daily Hamodia.

Internet without a filter, he added is "treif gamur," or completely unkosher.