PORTSMOUTH — Revisit McIntyre, a grassroots group of residents and business owners, has asked the General Services Administration if it can become a “consulting party” to the transfer of the McIntyre Federal Building to the city.

Attorney Paul McEachern, who represents Revisit McIntyre, sent a letter to GSA officials this week asking for the designation.

GSA owns the 2.1-acre property in the heart of Portsmouth’s historic downtown and near its popular waterfront.

Revisit McIntyre, McEachern states, is “concerned about the potential harmful effects that the proposed transfer would have on Portsmouth’s Historic District and its National Historic landmarks.”

The city is seeking to secure the property for free through the Historic Monument Program, which is also referred to as the Historic Surplus Property Program.

McEachern contends Section 106 of the National Historic Preservation Act “allows organizations like Revisit McIntyre to serve as consulting parties.”

Section 106 allows an agency to admit a consulting party to the proposed transfer, according to McEachern’s letter, “due to the nature of their legal or economic relation to the undertaking or affected parties or their concern with the undertaking’s effects on historic properties.”

The city is working to redevelop the property through the Historic Monument Program as part of a public-private partnership with its development partners Redgate/Kane.

If its application is approved by the National Park Service, which administers the program, Portsmouth can get the property for free from the GSA, which owns it. But the city must retain the federal building.

Redgate/Kane’s redevelopment plan calls for renovating the McIntyre for office space, and building two new mixed-use buildings with commercial and retail on the first floor, and 76 high-end apartments above. Fifty-eight of the apartments will be one-bedroom and 18 will be two-bedroom and they will include a total of 92 covered parking spaces. The average rent for the apartments will be $2,975 a month.

Michael Kane, president and chief executive officer of The Kane Company, could not immediately be reached for comment Friday.

Revisit McIntyre is opposed to the plan and is pushing the City Council to restart the redevelopment process.

In his letter to GSA officials, McEachern states the group’s purpose “is to ensure that decision makers at the federal, state and local levels have the information they need to assess the proposed development before deciding the McIntyre building’s fate.”

Revisit McIntyre was formed, McEachern said, when “it became clear that the city of Portsmouth decided to acquire” the building through the Historic Monument Program, without considering “other options that would better serve the city, its residents and business owners.”

He further contends in the letter that the proposed redevelopment “would drastically change the downtown, destroying the essential character of Portsmouth’s Historic District.”

“The traffic, aesthetic and visual effects (of the redevelopment) would be strongly felt on Bow, Chapel, Daniel and Penhallow streets, which encircle the McIntyre building,” McEachern said.

As a consulting party, Revisit McIntyre could help the GSA identify the potential impacts of the proposed property transfer and redevelopment, McEachern adds.

The letter, which is dated July 2, was addressed to Christopher Averill, GSA’s regional administrator, and Nancy O’Connell, GSA’s regional counsel.