An ambitious $2 billion project to refurbish the aging U.N. building was launched yesterday with the ground-breaking for a temporary building on the northern lawn of the U.N. campus, east of First Avenue.

The project, scheduled to be completed by 2013, is designed to modernize the landmark headquarters, which first were occupied in 1952 and have not been refurbished since. Hazardous substances, including asbestos, are to be removed, while new safety features, updated telecommunications systems, and environmentally oriented devices will be installed.

Staffers will move for the duration of the construction project to several nearby office buildings, while the temporary building will host U.N. meetings.

One of the party favors handed out yesterday to guests - among them top U.N. officials and ambassadors, and Mayor Bloomberg's sister, Marjorie Tiven, a liaison between the city and the  United Nations  - was a gold-colored lapel pin in the shape of a shovel inscribed with the letters "U" and "N."

BYLINE: Staff Reporter of the Sun