South Africa's ailing economy cannot afford more mine labor unrest, Finance Minister Pravin Gordhan said on Monday, as the platinum industry's main trade union served notice on the world's top three producers that it planned to strike this week.

A series of sometimes violent strikes in the factory and mining sectors constrained growth to a sluggish 2 percent in 2013, hampering efforts by President Jacob Zuma's government to create badly needed jobs as it braces for elections this year.

The African National Congress has swept elections since overturning white minority rule in 1994, but the party Zuma now heads faces growing criticism that it has failed to lift millions of blacks out of poverty during 20 years in power.

Platinum producers Anglo American Platinum (AMSJ.J), Lonmin (LMI.L) (LONJ.J) and Impala Platinum (IMPJ.J) said they had received notice from the Association of Mineworkers and Construction Union (AMCU) to strike in 48 hours, setting the stage for another crippling wave of unrest.

The chamber of mines, which represents bullion producers, said it was seeking a court order to block plans by the AMCU to down tools at Sibanye Gold's (SGLJ.J) Driefontein mine, Harmony Gold's (HARJ.J) Kusaselethu and Masimong mines, and at AngloGold Ashanti's (AGLJ.J) local operations.

The AMCU, which has a record of militancy, has rejected a 8 percent pay hike that rival union National Union of Mineworkers (NUM), which still represents most gold miners, agreed with producers last year.

The rand hovered close to recent five year lows after news of the planned strikes and Gordhan's warning, with scope to extend its nearly 4 percent losses against the dollar in the first three weeks of the new year.

Renewed labor strife in Africa's biggest economy will raise a red flag for ratings agencies after more than 50 people died during violent mine protests in 2012 that triggered downgrades from Moody's, Fitch, and Standard and Poor's and helped knock about 25 percent off the rand's value.

"The platinum industry needs to seriously get around the table," Gordhan told state broadcaster SAFM in an interview on Monday. "We can least afford another round of strikes that will act as a destabilization to the platinum sector, which has had increasing difficulties over the last 18 months."

STRIKES CONSTRAIN SOUTH AFRICA RATING

Earlier this month, Moody's cited weakening productivity and strike-related business losses, exacerbated by declining terms of trade, as a major credit challenge for South Africa.

"The economy has never fully recovered its momentum following the global recession in 2009, partly due to domestic political and economic turbulence ignited by violent labor unrest and the associated uncertainty that it has created," it said.

Demands for wage increases well above inflation of 5.3 percent will also worry the Reserve Bank, which has been blocked from further policy loosening by price pressures stemming from the rand's weakness.

The central bank will likely keep interest rates at a four-decade low of 5 percent at its first policy meeting of the year next week.

At Anglo American Platinum and Lonmin, the AMCU is seeking a minimum monthly wage of 12,500 rand ($1,200) for entry-level workers - more than double current levels, under the populist banner of a "living wage".

At Impala, the union scaled back its demand late last year to just over 8,500 rand a month.

The NUM said on Friday it had accepted overall wage increase offers of between 9.8 and 11.8 percent from mid-tier platinum producer Northam Platinum (NHMJ.J) in a bid to end a 75-day strike by more than 7,000 miners.

Companies have said they can ill afford steep increases as power and other costs soar while prices for platinum, used in pollution-reducing automobile catalytic converters, remain depressed.

($1 = 10.8370 South African rand)