Mayor Bloomberg is giving a boost to the gentrification trend that has been rapidly transforming the character of the South Bronx.

Atop the steps of the Bronx Civic Center, with Yankee Stadium at his back, the mayor yesterday layid out a three-part South Bronx initiative that is expected to bring more than 8,000 housing units, 800,000 square feet of commercial space, and greens to areas surrounding Melrose Commons, the Bronx Civic Center, and the Grand Concourse.

The All-Star Game is coming to Yankee Stadium in four weeks, and the mayor contrasted the prestige it will bring to the South Bronx with the despair of years past indicated by sports broadcaster Howard Cosell’s famous phrase: “The Bronx is burning.”

“After years of both public and private underinvestment, today the South Bronx is seeing some $3 billion of new investment in housing, shopping, mass transit infrastructure, and schools,” Mr. Bloomberg said.

He said the South Bronx initiative was a way to extend this growth, calling it “a winning formula” that has already been successful in places such as Long Island City and Greenpoint-Williamsburg.

Scheduled projects include a sandy park along the Harlem River waterfront, extended bus service south on 149th Street, and rezoning and streetscape development at the Civic Center and the Grand Concourse aimed at attracting retailers and adding appeal to residential neighborhoods. By 2010, in addition to the new Yankee Stadium, the mayor wants to have 1,400 new housing units and half of the total planned retail space either built or under construction.

One opponent of the initiative is an independent journalist who has lived in the Bronx for 25 years, Raphael Alequin, 75. He said the mayor’s planned developments could lead to current South Bronx residents being driven out.

“When they develop, the rent is going to go high,” he said. “That will create a community of homelessness.”

The city Economic Development Corp. president, Seth Pinsky, said the costs for the three area developments had not yet been determined or allocated, but would be estimated as the project moves past the planning stage.

Also present were a deputy mayor for Economic Development, Robert Lieber, the city planning commissioner, Amanda Burden, and the executive director of Nos Quedamos, a citizen housing preservation committee, Yolanda Gonzalez. The president of the Bronx, Adolfo Carrion, did not attend the announcement.