A vocal dwarf activist for issues ranging from gay and disabled rights to transportation was struck and killed by a taxi as he left a meeting on the Lower East Side, authorities said yesterday.

Harry Wieder, 57, walked with crutches from a meeting of Community Board 3 Tuesday evening at PS 20, then crossed Essex Street in the middle of the block and was hit by a yellow cab, fellow board members said.

Wieder was rushed to Bellevue Hospital, where he was pronounced dead.

The diminutive crusader got his start as an activist in the early 1980s when he came out as gay and got involved in the rights group ACT UP. Wieder became a fixture at community-board meetings, rallies and hearings and was well-known on the city’s political scene.