* Ten-day strike to continue - sources
* Workers demanding 12-15 pct rise
* NUMSA to announce decision on Sunday (Adds NUMSA comments)
By Wendell Roelf
CAPE TOWN, July 11 (Reuters) - Regional branches of the National Union of Metalworkers of South Africa (NUMSA) have rejected the latest wage offer from employers, two union sources said on Friday, potentially drawing out a 10-day strike that is already hurting production.
The stoppage by 220,000 NUMSA members comes hard on the heels of a five-month strike in the platinum mining sector that dragged Africa’s most advanced economy into contraction in the first quarter.
Union members downed tools on July 1 demanding pay rises of 12-15 percent. In their latest offer, employers proffered a 10 percent wage increase this year, 9.5 percent in 2015 and 9 percent the following year, officials said.
NUMSA branches in seven of South Africa’s nine provinces had chosen not to accept the offer, one of the NUMSA officials said.
“We are still open for engagement with the employer and the strike is continuing,” one of them told Reuters.
The rand currency weakened slightly after the news.
NUMSA spokesman Castro Ngobese declined to comment on the report, saying that the union’s formal decision would be announced on Sunday.
“We are still busy with feedback,” Ngobese said.
The sector’s main employers’ group, the Steel and Engineering Industries Federation of South Africa (SEIFSA), said it was yet to receive an update from NUMSA.
The walkout has hit components factories supplying U.S. car manufacturer General Motors’ South African plant, which has been forced to stop production for a week.
This year’s industrial unrest has hurt the economy and hit South Africa’s reputation as an investment destination, with SEIFSA saying the local head of U.S. vehicle maker Ford Motor was under pressure from head office to sell up its operations.
However, Ford, which has invested over 3.4 billion rand ($317 million) in two plants producing the Ranger pick-up truck for the domestic market and export to nearly 150 foreign markets, says it is committed for the long-term.
A four-week strike last year by more than 30,000 NUMSA members at major automakers cost the industry around $2 billion. ($1 = 10.7165 South African Rand) (Writing by Helen Nyambura-Mwaura; Editing by Ed Cropley)