* Strikes loom across platinum belt
* Impact on spot platinum price muted so far
By Ed Stoddard
JOHANNESBURG, Oct 31 (Reuters) - South Africa's National Union of Mineworkers (NUM) has given junior producer Northam Platinum 48-hour notice of its intention to strike after wage talks broke down, a union negotiator said on Thursday.
A government mediator on Monday granted NUM permission to call for a strike at Northam.
"We have given them the notice and from today they have 48 hours to come back with another offer or we will strike," NUM negotiator Ecliss Tantsi told Reuters.
NUM is demanding that the company raise wages by between 22 percent and 43 percent, depending on the level of employees and raise housing allowances by 69 percent.
Northam, a mid-tier producer, said it had improved its offer, which NUM rejected, to include increases of 7 and 8 percent in the first year, above the current inflation rate of 6 percent.
"The company's revised offer would add approximately 117.3 million rand ($12 million) to the current annual wage bill of 1.3 billion rand," Northam said in a statement.
The strike is expected to begin from the night shift on Sunday should the parties fail to reach an agreement within the next 48 hours, it said.
The dispute involves the workforce at Northam's Zondereinde operation, its primary mine which accounts for the vast majority of its annual production of about 300,000 ounces a year.
Northam's bigger rivals, Anglo American Platinum, Impala Platinum and Lonmin are also currently in wage talks.
The Association of Mineworkers and Construction Union (AMCU) said on Monday its members voted to strike at Implats after wage talks failed, but it would not immediately give the company a 48-hour notice.
AMCU has also declared a wage dispute with Amplats and a government mediator will try resolve the dispute.
Looming strikes on South Africa's platinum belt have had little impact on the spot price of the previous metal because demand remains relatively weak while there is excess supply in the industry's pipeline.
But they would inflict more damage on Africa's largest economy, which has been hit by a spate of strikes this year in other sectors including the auto industry, and pressure the volatile rand currency.
Northam's share price fell over 2 percent on the news.