The Islamic cultural centre drew national attention when it was embroiled in controversy last year [EPA]

An Islamic cultural centre close to the site where New York's World Trade Center once stood has opened quietly in spite of scenes last year of vehement protests from those who said the area should not house a mosque.

The opening ceremony for the Park51 centre on Wednesday featured a photo exhibit called "NYChildren", displaying over 160 portraits of immigrant children living in New York.

Sharif El-Gamal, the center's developer, said the biggest error on the project was not involving the families of 9/11 victims from the start.

"We made incredible mistakes," El-Gamal told The Associated Press in an earlier interview at his Manhattan office.

The building at 51 Park Place, two blocks from the World Trade Center site, includes a Muslim prayer space that has been open for two years.

The Islamic center sparked a national debate last year about the place of Islam among the numerous religions practised in the US.

By contrast, Park51 has vowed to offer "social and recreational services, as well as world-class health, wellness and educational facilities", alongside a religious focus.

"Presently, Park51 is opening its doors to New Yorkers of all backgrounds for interfaith workshops, films and lectures," the group said on its website, as a mosque has already been operating on the site for two years.

Last year thousands of people marched through New York on the ninth anniversary of the 9/11 attacks, facing off in angry debate under a heavy police presence as they protested for or against the project.

The row was stirred in August 2010 by threats from an evangelical Christian pastor to burn hundreds of Korans unless the mosque was moved.