Mayor Marty Walsh and at-large City Councilor Ayanna Pressley on Monday outlined a plan for 152 new liquor licenses across Boston - a plan that could mean a significant number of new licenses for Dorchester and Mattapan.

Under their proposal, which needs approval of the city council, the state legislature and the governor, Dorchester and Mattapan would each get a total of at least 15 new liquor licenses, doled out over three years. Unlike the additional liquor licenses the state gave Boston in 2014, these licenses could not be granted in other neighborhoods - if 15 Mattapan restaurants or bars don't apply for the licenses, the Boston Licensing Board would keep them on hand until enough Mattapan places do apply.

The proposal would also essentially grant an unlimited number of licenses at the South Bay Town Center now under construction, by creating a class of "umbrella" licenses for any developments of at least 500,000 square feet, such as South Bay and the even larger Seaport Square project in South Boston.

Under this proviso, similar to a license deal already in place for Logan Airport, the owners of such developments would get a single site-wide license that they could then use for tenants with restaurants, subject to approval by the Licensing Board, without affecting the number of licenses available in the rest of the city.

Last year, the City Council agreed South Bay Town Center would need at least a dozen liquor licenses for restaurants and a planned cineplex, and said it wanted Seaport Square to get at least three liquor licenses.