CAPE TOWN (Reuters) - U.S. motor company Ford (>> Ford Motor Company) has suspended production at one of its South African plants and Japanese car-maker Toyota (>> Toyota Motor Corp) plans to follow suit as a manufacturing workers' strike hits suppliers of car components.

The two-week-old strike by 220,000 NUMSA union members, who are seeking 12-15 percent annual increases, follows on the heels of a five-month strike in the platinum sector that stunted economic growth and export earnings.

The strike, which has hit the supply of beverage cans made by packaging firm Nampak (>> Nampak Limited), has damaged wider investor sentiment in Africa's most advanced economy, which is teetering on the brink of recession after a first-quarter contraction caused in part by the platinum strike.

Ratings agency Standard & Poor's cut South Africa's credit rating last month while Fitch put it on negative watch, both citing poor growth prospects mainly because of strikes.

Ford spokeswoman Alicia Chetty said: "Production at our Silverton assembly plant has been temporarily suspended due to the strike." She said only the company's Pretoria plant was affected and its other plant in Port Elizabeth was operating normally.

Jeff Nemeth, Ford's South Africa head, told Talk Radio 702 suspension at the plant - which assembles the Ford Ranger pick-up truck - would mean the loss of about 350 units a day.

Nemeth said continued disruptions in the flow of products might affect corporate investment decisions in Africa's most developed but ailing economy.

Toyota said it would halt some production from Tuesday because of supply chain problems related to the stoppage.

"Toyota will close two production lines from Tuesday at our Durban plant," spokeswoman Mary Willemse said.

The manufacturing strike also forced General Motors (>> General Motors Company) to close its assembly plant in the southern city of Port Elizabeth over a week ago, despite efforts by Labour Minister Mildred Oliphant to mediate between the union and employees.

"CRITICAL"

Mercedes Benz said supply lines to its assembly factory were reaching "critical" stress levels and an industry body warned more car-makers could be forced to halt production.

"Things are beyond dire. We have exhausted stockpiles we managed to build up in the months leading up to this strike and I expect more companies to halt production should the strike continue," Ken Manners, vice president of the auto component manufacturing body NAACAM told Reuters.

Production at BMW (>> Bayerische Motoren Werke AG), VW (>> Volkswagen AG) and Nissan (>> Nissan Motor Co., Ltd.) was normal, although company officials said on Monday they were monitoring the situation closely.

Those affected include construction companies Murray & Roberts (>> Murray & Roberts Holdings Limited) and Aveng Ltd (>> Aveng Limited), which are working on the construction of two major power plants for state power utility Eskom.

NUMSA rejected the latest pay offer from employers in the steel and engineering sector on Sunday and called on its striking members to intensify the industrial action.

Employers have offered pay rises of 10 percent in the first year, 9.5 percent in the second year and 9 percent in the third year. But unions also have grievances about the role of labor brokers in industry and do not want to be bound to a multi-year agreement, preferring a one-year deal instead.

NUMSA met the main employer body, Steel and Engineering Industries of South Africa (SEIFSA), on Monday to formally reject the offer.

Spokesman Castro Ngobese said SEIFSA - which said on Friday it would take its latest offer off the table if it is rejected - has taken his union's latest demand to its members for consideration.

"Meanwhile the strike continues indefinitely," Ngobese said, adding union leaders were due to meet on Tuesday to consider ways to intensify the strike.

Smaller union United Association of South Africa (UASA), which represents about 20,000 workers in the sector, said it was awaiting a reply from employers on questions about the offer.

"We expect an answer by tomorrow and that will put us in a position to say if we accept or reject it but chances of accepting look good," Johan van Niekerk, UASA spokesman, said.

Separately, about 200 workers downed tools at unlisted Cape Town-based wine maker DGB, demanding a 10 percent wage hike, union leaders said. DGB, which makes some well-known brands, is offering a 7 percent raise.

(Additional reporting by Tiisetso Motsoeneng in Johannesburg; Writing by Olivia Kumwenda-Mthambo; Editing by Ruth Pitchford, Hugh Lawson and Jane Merriman)

By Wendell Roelf