NEW MILFORD — Speculation about the potential development of a Walmart Supercenter on Route 7 brought neighbors and the owners of competing shopping centers - and their lawyers - out to a New Milford Planning Commission meeting Thursday night. The commission voted 3 to 2 to clear the way for a zone change on 39.5 acres behind the Windmill Diner to now be considered by the town’s Zoning Commission.

The split was along party lines - with Republicans finding that the zone change is in compliance with the town’s Plan of Conservation and Development, and Democrats against.

And Mayor David Gronbach on Friday criticized Republican Town Councilor Paul Szymanski, who is representing the owners of the property, for refusing to reveal what is intended for the property.

“If, as is widely believed, a Super Wal-Mart is proposed, I along with a majority of the business community will oppose it,” Gronbach said.

The amendment would change zoning of the land, known as the Docktor brothers property, from Restricted Industrial to Industrial, allowing retail uses on the property. Walmart has tried before to open a Supercenter in New Milford, but has been unsuccessful.

The Zoning Commission will consider the proposal in a meeting on Tuesday night.

“I urge concerned citizens and business owners, regardless of political party, to voice your opinion,” Gronbach said.

Discussion on Thursday centered on whether the town’s plan specifically requests that a market survey to establish the town’s current zoning and land-use be done before such an amendment is forwarded to the Zoning Commission.

Szymanski, president of Arthur H. Howland & Associates, which put the amendment forward on behalf of the executors of an estate that owns the property, argued that the a zone change was needed to sell the land, which has languished unused for more than a year and was only used as a small mining operation before that.

Commission Chairman Jon Seidman agreed Thursday night with Town Planner Kathy Castagnetta’s previous request that a survey be done before the commission vote that the amendment complied with the Plan of Conservation & Development plans.

Although the commission voted that the proposed change is OK according to the the town’s 2010 plans, two Democratic commission members, the town planner, local property owners and several members of the public opposed the recommendation and urged the commission to do a study.

Szymanski argued that the POCD does not “require” a market study, but instead says one “should” be done.

Commission Democrats, citing existing empty storefronts, said they would like to assess the town’s need for new retail before any zoning amendment opened the door for more.

They also said that it makes their job of evaluating a proposed change difficult if they aren’t told why people are requesting a zone change.

Szymanski declined to comment to the News-Times before or after the meeting, other than saying, “I’m satisfied with the result,” Thursday night.

Republican commission members agreed with Szymanski that the POCD says that the property could be zoned Industrial, and that the re-zone would make the large parcel easier to sell.

“The POCD is our bible,” said Republican Commission Member Joseph Girardot. “It is not for us to judge the wisdom of the proposed project, which we don’t know.”

One estate executor has also declined comment, the other could not be reached, and Wal-Mart has not responded to several requests for comment.

Secrecy surrounding the proposed amendment prompted a half-dozen people to attend the Thursday meeting, though Girardot raised questions about allowing them to comment, saying it would result in an illegal “ad-hoc” public hearing. He requested an opinion from the town’s lawyer before the meeting continued.

The meeting was recessed 15 minutes soon after a lawyer for Willing Biddle, whose company owns several commercial properties, including the Stop & Shop complex and TJ Maxx shopping center, argued for a market study.

During those 15 minutes, Republican commission members, who constituted a majority of the board, left the room and spoke together in a hallway. Afterwords, Girardot motioned that if the lawyer finds that the public comment was “illegal,” it be struck from the record.

Residents and town officials believe the zone-change proposal to be the work of Wal-Mart because the company often moves on a property without attaching its name to the project until the very end. In 2013, a realty company called Saber New Milford LLC submitted an application to the town to build a 154,000-square-foot store on Danbury Road. The land was owned by Westrock Development, which was in talks with Wal-Mart to lease the building, The News-Times reported that year.; 203-731-3411; @bglytton