A nonprofit group is suing the city to prevent the Elizabeth Street Garden from being redeveloped for affordable housing, the latest step in a years-long battle that has galvanized open space activists to preserve the half-acre city-owned plot in Nolita.

“The fight is not over,” said Joseph Reiver, the executive director of Elizabeth Street Garden, the group that brought the lawsuit. “It’s just getting started.”

The lawsuit, filed on Tuesday in state Supreme Court, accuses the city and the Department of Housing Preservation and Development of “arbitrarily, capriciously,” and illegally failing to consider a host of environmental impacts that would result from the destruction of the garden.

The group is asking a judge to order HPD to issue an environmental impact statement [EIS], a critical city planning document that would evaluate a list of effects the project would have on the community, including access to open space, air quality, neighborhood character, and socioeconomic conditions. Normally an EIS is required as part of the city's land use process, but in November the HPD concluded such a step was unnecessary because the garden’s removal would not have a significant adverse impact.

The battle over the garden has raised a debate about competing land use priorities in a city struggling with a dearth of both affordable housing and open green space.

Councilmember Margaret Chin, who represents the neighborhood, has argued that the redevelopment plan, which would build 121 units of affordable housing for seniors, answers a critical and longstanding need in the city. But the garden’s supporters and urban planning critics have said that affordable housing should not come at the expense of open space, especially one as notable as Elizabeth Street Garden. Curated with plantings and sculptures, the garden has been described as an urban oasis.

“It’s a false choice,” said Norman Siegel, the prominent civil liberties attorney who is representing Elizabeth Street Garden. “We can and must have both open green space and affordable housing.”

Siegel noted that under both the Bloomberg and de Blasio administrations, New York City has made a commitment to preserve and expand open green space.

In an affidavit accompanying the suit, Adrian Benepe, the former parks commissioner, testified that the destruction of the garden was “directly contrary” to the city’s public policy, which over the years has sought to use open green space as a way to mitigate the effects of climate change.

A spokesperson for HPD said the department could not comment on ongoing litigation.

The lawsuit also opposes the city’s attempt to consider Elizabeth Street Garden as an Urban Development Action Area under a city program that makes developers of land "in need of urban renewal" eligible for a 20-year tax exemption. Siegel said there was no way Elizabeth Street Garden, which is located between Prince and Spring streets in one of the city’s trendiest neighborhoods, merited such a designation.

“There’s no way that anyone can go to that area and conclude it’s a slum,” he said. “What kind of manipulation is going on here?”

Despite opposition from Community Board 2, the plan to redevelop the garden is currently making its way through the city’s uniform land use review procedure. Last month, Manhattan Borough President Gale Brewer, whose role, like the community board's, is only advisory, issued a favorable recommendation.

The project must next go before the City Planning Commission, before moving on to the City Council and the mayor for final approval.

However, should HPD be ordered to issue an environmental impact statement, the ULURP process would start all over again, Siegel said.

A second group is expected to join the legal fight. Friends of Elizabeth Street Garden, another nonprofit involved in preserving the space, has said it expects to file a lawsuit as early as Thursday.

Reiver, whose father, Allan Reiver, built the garden in 1991 on a vacant lot he leased from the city, said the city had ignored the community’s pleas to save what amounted to an iconic community green space. His group has been working to raise money for its legal efforts. Last week, he and several other volunteers distributed leaflets at a city rezoning meeting for Soho and Noho. During the meeting, he critically observed that the city planning map did not identify Elizabeth Street Garden as a green space.

“They may say they stand for community input,” he said. “These days, we find fewer and fewer people have faith in such a process.”