(Reuters) - The Michigan Senate voted to approve a right-to-work bill on Thursday that would weaken labor union power, in a move expected to spark a bitter fight with organized labor in the home of the U.S. auto industry.

The bill was passed by a 22-16 vote in the Senate, followed by cries of "shame" from protesters observing the vote. The state House passed similar legislation earlier in the day.

Governor Rick Snyder said earlier that he wanted Michigan to be the 24th state to adopt a "right-to-work" law making payment of union dues optional.

(Reporting By Mary Wisniewski and David Bailey; Editing by Cynthia Johnston)