The Yankees’ proposal to build a new stadium is the subject of a public hearing before a City Council subcommittee today, inaugurating a final round of sparring between opponents and supporters of the project in advance of a final council vote slated for April 5.

The new stadium and infrastructure improvements, estimated to cost about $1 billion, would be built near the existing ballpark, displacing about 22 acres of parkland. The parkland would be replaced at several nearby sites, but some members of local community and good government groups say the Yankees are not giving enough back to the surrounding community, one of the poorest in the city. The local community board rejected the plan last year.

Last week, details were released about a draft agreement between the Yankees and local politicians under which the Yankees would give about $28 million over the next 40 years to a panel that would distribute the money to local nonprofits. It would also include $100,000 a year for upkeep of neighboring parks, $100,000 for local sports groups, and 15,000 free tickets a year for Bronx schools, youth groups, and seniors.

Council Member Helen Diane Foster, a Democrat of the Bronx, said yesterday that the terms of that agreement articulated so far are a “joke” and are “insulting to the community.”

Ms. Foster, the elected official who has been most critical of the project, said the majority of the Bronx delegation, while supportive of the project as a whole, has serious concerns and unanswered questions about the current proposal.

“We are not there. It definitely is not a done deal yet,” Ms. Foster said, predicting changes to the plan or the community benefits agreement before next Wednesday’s vote. “We are fans of the Yankees, but we are not fans of the Yankees organization.”

A spokeswoman for the Yankees, Alice McGillion, said discussions about the agreement with the community are under way with the “political leadership” of the Bronx.

In land use matters, the City Council typically votes along with the local council member or the consensus of the delegation from the borough where the project is located.

Supporters, who include the mayor, the governor, the president of the Bronx, Adolfo Carrion, and the city’s Department of Planning, say the new stadium would be the biggest private investment in Bronx history, would create jobs, and would help to spur an ongoing revitalization of the community.

Opponents vow to mount a legal challenge if the project is passed as proposed.

If the City Council gives final approval to the proposed 51,800-seat stadium, the city will spend $135 million to create new parks and enhance infrastructure, and the state will pay $70 million for additional parking facilities. The Yankees would pay about $800 million for the construction of the stadium, which would begin this season.