JOHANNESBURG (AFP) - Around 3,000 workers at the world's number two platinum miner Implats went on strike on Tuesday to protest the dismissal of one of their colleagues, the company said, adding to tensions in the restive mining sector.

The company employs some 33,000 workers at its mines near the north-western town of Rustenburg in South Africa's platinum belt, the world's largest.

"It's a small strike," company spokesman Bob Gilmour said. "One of their members was dismissed due to a disciplinary action yesterday and they didn't come to work this morning." "We are obviously negotiating and hope we will resolve it quickly." Implats has largely been spared in the wave of violence that hit South Africa's mining sector in the last half of 2012.

Unrest in the sector has increasingly become a sore thumb for the country, prompting President Jacob Zuma last week to call on workers and mine managers to resolve their disputes without violence or strikes.

Troubles in the sector partly contributed to the country's economic growth hitting a fresh low of 0.9 per cent in the first quarter of the year.

On Monday, a union leader was shot dead and another wounded at platinum miner Lonmin's Marikana mine, the same area where police trying to contain a violent strike shot dead at least 34 miners last August in what they claimed was self-defence.