The Bloomberg administration announced plans to officially challenge the U.S. Census Bureau's population count for New York City. The challenge comes in response to the bureau's tally of 8.175 million people within the five boroughs — a headcount about 250,000 below what local officials believe to be accurate.

The announcement was made by Mayor Michael Bloomberg in Jackson Heights, Queens, where he joined with an array of local, state and federal elected officials.

Many of them echoed a common complaint: that census workers had likely failed to gain access to thousands of housing units, namely in immigrant enclaves in Brooklyn and Queens, and had subsequently written off those homes as vacant when they were in fact occupied.

The city's challenge will be made under what's known as the Count Question Resolution process, which will be open for submissions as early as June 1, for a two-year period.

Bloomberg said he hoped the city's submission would prompt the Bureau to "take another look at the data from Brooklyn and Queens, and check to see if errors were made in compiling the final results."

Census officials were not available to comment Sunday on the merits of a challenge, but late last week Census Director Robert Groves acknowledged the frustrations of city leaders dealing with what they considered undercounts, and said census workers would eventually evaluate the merit of various claims.

Among the officials who gathered with Bloomberg to protest the figure were Senator Charles Schumer and representatives Nydia Velasquez and Anthony Weiner. Some officials have noted that other census estimates in recent years have been far larger than the one in question.

"For every hundred people that they don’t count," said Velasquez, "New York City stands to lose $1.2 million" in federal funding over the next 10 years.

The city's chief demographer, Joseph Salvo, said he and other officials are increasingly convinced that an "operational breakdown" on the part of census workers last year had contributed to an undercount.

"We suspect maybe in some of these areas, there were operational problems, that maybe they didn't go back as much as they had to go back, or maybe they didn’t talk to the neighbors enough," he said.

Salvo noted that the census listed "block after block" of vacant housing units.

"So we are currently evaluating this, but we are certain from our own administrative data, that this was not the case, at all," he said. "When you have a vacancy level of 20, 30 percent, you start to see deterioration. Boarded up houses. There is no such thing."