Hyundai  said Tuesday it had reached a tentative wage deal with labour unions to end a series of damaging partial strikes at the world’s fifth largest automaker.

The accord was hammered out late Monday, the company said in a press statement, and will need to be confirmed by the union membership at a vote on Wednesday.

“We did our best. We hope this deal will be approved,” said union spokesman Hwang Ki-Tae.

Tens of thousands of Hyundai workers have staged sporadic strikes since August to push their demand that regular bonuses be considered part of the basic wage used to calculate rates for overtime, holiday shifts and pensions.

The company said incorporating bonuses in the calculations would inflate its wage bill by 10 percent.

Under the deal reached Monday, the issue will be handled by a new management-union consultative body which will seek a resolution by the end of March next year.

The agreement also included bonuses and incentives totalling 8.9 million won ($8,400) plus payments equivalent to 4 1/2 months’ salary and a rise of 98,000 won in basic salaries.

Unionised workers at Hyundai’s affiliate Kia Motors Co. have also been involved in the wage dispute.

Hyundai says the strikes in August and the workers’ refusal to work overtime have cost Hyundai some 32,000 cars in lost production and 700 billion won ($673 million) in sales.

Hyundai’s second-quarter net profit slumped 6.9 percent from a year earlier.