SEOUL (Reuters) - Hyundai Motor Co's labor union said on Tuesday its members have approved a tentative wage deal its leadership had negotiated with management.

Terms were renegotiated after union members rejected an earlier tentative deal in late December, marking the first time the South Korean automaker failed to reach a wage deal by the end of the year.

The agreement will allow Hyundai to focus on improving sales after a slump in 2017 when China sales were hit by a diplomatic row between Beijing and Seoul over South Korea's deployment of a U.S. anti-missile defense system.

The union said in a statement that 61.1 percent of voters approved the deal whereas 38.4 percent rejected the terms. The remaining votes were invalid.

Hyundai did not have an immediate comment.

(Reporting by Joyce Lee; Editing by Edwina Gibbs)