(Recasts and updates throughout with more detail)
By Daina Beth Solomon
MATAMOROS, Mexico, Feb 28 (Reuters) - Workers at Mexico's Tridonex auto-parts plant on Monday voted overwhelmingly in favor of appointing a new union, in a poll being closely watched in the United States after allegations of worker rights abuses at the plant.
Independent union SNITIS garnered 1,126 votes, outstripping the 176 votes for the current union CTM, which is part of one of Mexico's biggest labor organizations.
Workers at the plant in the northern Mexico city of Matamoros began campaigning about two years ago to replace a union that they accused of failing to push for higher wages.
Tridonex's unlisted U.S. parent, Cardone, faced U.S. government scrutiny last year in one of the first labor complaints under a new regional trade deal, the United States-Mexico-Canada Agreement (USMCA), after workers at the plant said they were being denied the right to freely select their union.
More than 80% of eligible workers cast ballots on Monday, in a vote that U.S. Trade Representative Katherine Tai said was being closely watched.
The election came weeks after the CTM union lost its 25-year hold at General Motors in the central city of Silao to an upstart group in an election following another complaint under the USMCA trade deal.
(Reporting by Daina Beth Solomon; Editing by Jacqueline Wong and Jane Wardell)