Suffolk County lawmakers plan to vote Tuesday on a bid to buy a 21-acre property in Middle Island where a shopping center was demolished last year.

The county’s bid to buy the land from Garden City-based developer Wilbur Breslin is part of a plan by Suffolk and Brookhaven Town officials to build a park at the Middle Country Road site, and develop athletic fields there for youth sports leagues, officials said.

Under the plan, the county would buy about one-third of a 75-acre parcel where an abandoned Kmart was torn down last year. Breslin paid for the demolition, which took place days after the body of a gunshot victim was found in a nearby wooded area.

Legis. Sarah Anker (D-Mount Sinai) said the park would transform “a commercial, blighted parcel into a community park that will benefit everyone — especially the children.”

Anker said she could not disclose the proposed purchase price. Breslin did not respond to a request for comment.

In addition to the county buying 21 acres, the state would purchase 28 acres of land for open space preservation, and Breslin would keep the remaining 26 acres for development, Anker said.

Middle Island Civic Association president Gail Lynch-Bailey said residents had long complained about the vacant store, which had been empty for a decade before it was demolished.

“It’s so important to have something positive on this long-blighted parcel,” she said. “To have blight there is just awful.”

The park plan is modeled on an earlier effort to build Heritage Park in Mount Sinai. In that case, the county bought the land and Brookhaven built a park managed by community leaders.

The park in Middle Island also would be built by the town, and it would be run by the Longwood Youth Sports Association, or LYSA, which organizes baseball, soccer and lacrosse leagues for more than 3,000 children in Middle Island, North Shirley, Ridge, Coram and Gordon Heights.

LYSA president Tom Bove said teams currently play on fields owned by the Longwood school district. LYSA teams can only play when the schools are not using them, he said.

“We have the largest sports youth club and no place to play other than school fields,” Bove said. “We’re trying to become totally independent of the school fields.”

Bove said the park also would have walking trails and a playground.

Lynch-Bailey said many residents would support Breslin if he decided to build new stores on the remaining 26 acres.

“There’s all sorts of wonderful possibilities for him on that parcel. We’re hoping he says this as a win-win for him and his partners,” Lynch-Bailey said. “It really could be a legacy for Wilbur Breslin in Middle Island.”