New York Mayor Michael Bloomberg administration has filed a formal challenge to the 2010 census on Wednesday, alleging it may have overlooked "tens of thousands" of Queens and Brooklyn residents at the least.

In March, the U.S. Census Bureau reported that New York City had grown by 2.1 percent to a 8.175 million residents during the first decade of 2000. according to a Wall Street Journal report, the initial count for Brooklyn suggested a growth of 39,000, a 1.6% increase, while Queens added 1,300 residents, less than 1%. 

There are at least 50,000 residents of Brooklyn and Queens living in homes and apartments considered as vacant by the bureau, suggested Bloomberg's letter. City officials believed that if those were counted, the city's official population would be between 8.3 and 8.4 million. 

"I recognize that enumerating the population of New York City is a Herculean and unenviable challenge, given the city's large, diverse and dense population, which lives primarily in difficult to count housing arrangements," Bloomberg wrote in his letter to Robert Groves, the director of the U.S. Census Bureau.  

However, "numerous data sources cited in our submission refute the prevalence of widespread vacant housing units in those areas, which are and continue to be among our most stable, growing and vibrant neighborhoods."

According to the data, city officials pointed to possible processing errors in classifying large numbers of housing units as vacant in Bay Ridge, Bensonhurst, Astoria and Jackson Heights.

A higher count could mean more money for federal aid and a bigger base for Census Bureau to compute subsequent annual population estimates before the next census in 2020.

As of last week, 48 other municipalities had filed challenges with the Census Bureau, while none of these are remotely as large as New York City.

"In all my years as a legislator, I have never seen a Census so poorly conducted," stated Sen. Charles Schumer. "The Census Bureau needs to conduct a recount immediately to get this right, and I will continue pushing them to do just that."

The city's challenge will be examined at the Census Bureau headquarters and could take months to resolve, reports the New York Times. If the claim is rejected, all options, including legal action, "remain on the table," according to Marc LaVorgna, a mayoral spokesman.

The Census Bureau did not comment on the issue, or specify how long it will take to analyze the city's challenge.