* Some 200,000 members of NUMSA union went on strike last week
* GM says has enough inventory for medium term
* No impact at Mercedes Benz, full production at Toyota
* Wildcat strike at platinum mine shows wider labour woes (Adds strikers at Implats mine to go back to work)
By Wendell Roelf
CAPE TOWN, July 7 (Reuters) - South Africa's metalworkers union said wage talks to settle a week-old strike would resume on Tuesday, offering some hope to an industrial sector plagued by disruptions in Africa's most advanced economy.
More than 200,000 National Union of Metalworkers of South Africa (NUMSA) members downed tools a week ago and are demanding wage increases of between 12-15 percent.
In a separate dispute, some 2,000 miners who had staged a smaller wildcat strike at one platinum mine since Friday indicated they were ready to return to work on Tuesday and agreed to formal wage talks, the mine company said.
The wider NUMSA-led strike action has dealt a further blow to the ailing South African economy, coming just two weeks after miners in the key platinum sector agreed a slightly higher wage deal to settle a five-month stoppage.
"If the employers can present something that we strongly feel we can take back to our members for a mandate, we will gladly do that," NUMSA spokesman Castro Ngobese said. "But in the absence of that, the strike continues."
Ngobese said the union had not received a revised offer. The Steel and Engineering Industry Federation of Southern Africa said last week that NUMSA rejected its 10 percent offer.
Employers and labour representatives met again with government officials on Monday as Pretoria intervened to try to break the deadlock costing the country's metals industry - which has shed hundreds of thousands of jobs the past decade - an estimated 300 million rand ($27.8 million) a day.
The union is also demanding that any pay agreements apply for a year only while companies want a three-year deal.
The strike has hit components factories supplying General Motors' South African plant. However, the U.S. auto maker said it had sufficient inventory for both domestic and export customers for the medium term.
"The strike in the metal and engineering sector has impacted upon supply of components to our production line, resulting in our line not being operational since July 3," GM spokeswoman Denise Van Huyssteen said. "To date we have lost three days of production."
German counterpart BMW brought forward a week of a pre-planned annual plant shutdown for maintenance last week, spokesman Guy Kilfoil said.
"We were going to close the plant at some point during the year for maintenance anyway. We just brought it forward because we knew the strike was coming," Kilfoil said, adding the factory would reopen on Tuesday.
Compatriot Mercedes Benz said there had been no impact so far at its local operations, while Toyota said it was still at "full production".
At Impala Platinum's Marula mine, some 2,000 miners affiliated to the National Union of Mineworkers (NUM) who had been striking since Friday indicated they would return to the shafts on Tuesday and press their pay demands through "formal channels", Implats spokesman Johan Theron said.
He said their precise demands remained unclear.
Implats, the world's second largest producer of platinum, and rivals Anglo American Platinum and Lonmin are still reeling from the five-month platinum sector strike that ended in late June.
That stoppage was led by NUM's rival, the Association of Mineworkers and Construction Union (AMCU), which eventually settled for wage hikes of up to around 20 percent.
The Marula operation was not hit by that strike as its NUM-affiliated workforce signed a wage deal last year.
But Theron said on Friday that it seemed the Marula miners now wanted the same wage deal that AMCU obtained for its members at other Implats mines.
($1 = 10.7975 South African Rand) (Additional reporting by Tiisetso Motsoeneng, Ed Stoddard, Helen Nyambura-Mwaura and Zandi Shabalala; Editing by Stella Mapenzauswa, John Stonestreet and Pascal Fletcher)