BERLIN, March 4 (Reuters) - Germany's top industrial

union is fighting for more influence at Tesla's

gigafactory outside Berlin, where staff are voting for a new

works council after a campaign marked by mud-slinging and legal

challenges.

Voting began on Monday at Tesla's Gruenheide plant, the U.S.

electric car maker's only European production site, with results

expected later Wednesday.

The current council is dominated by non-union members. The

IG Metall union is fielding 116 candidates in a bid to win a

simple majority - 19 of 37 seats. The union secured 16 in the

last election two years ago, when the council had 39 seats.

IG Metall has accused management of stoking anti-union

sentiment. Plant director Andre Thierig has countered that the

union is focused solely on boosting IG Metall membership.

"We are very satisfied with our election campaign. We are

running with a great team and our issues are clearly striking a

chord with our colleagues," IG Metall's lead candidate Laura

Arndt said in a statement to Reuters.

Works councils, elected by staff, are a cornerstone of

German labour relations, representing employees in talks with

management.

IG Metall dominates councils across German carmakers -

including Volkswagen, BMW and Mercedes

- but remains the underdog at Tesla, whose CEO Elon

Musk is outspoken in his criticism of unions.

Tensions peaked in February when Tesla accused an IG Metall

trade unionist of secretly filming a works council meeting and

filed a criminal complaint.

IG Metall dismissed the allegation as a "calculated lie".