JOHANNESBURG, Sept 1 (Reuters) - Talks between South Africa's mine workers' union and Impala Platinum (IMPJ.J) (Implats), the world's No. 2 platinum producer, began on Tuesday 1 September in a fresh attempt to end a week-long strike over wages.

The strike at Implats entered a second week on Monday 31 August, affecting the company's biggest mine, Rustenburg, and its smaller Marula mine. Implats' Springs metal refinery had not yet been affected by the industrial action, the union said.

Lesiba Seshoka, spokesman for the National Union of Mineworkers (NUM), South Africa's biggest union, said the meeting with Implats could well go late into the afternoon before any conclusion is reached.

"Negotiations are not something that you can know off the cuff what they will produce ... we can only remain hopeful that something positive will come out from it," he said.

Workers are demanding a 14 percent wage hike -- more than twice inflation at 6.7 percent -- plus transport and housing allowances. The company, facing lower earnings and rising costs, says it cannot afford that much and has offered 10 percent.

Seshoka said that while the union was hopeful on the talks, it would insist on its demands.

"At this stage we are really looking for our 14 percent," he said.

Implats spokeswoman Alice Lourens declined to comment on whether the company would be willing to come closer to what the union is asking for, but said Implats was losing up to 3,500 ounces of platinum a day across the group due to the strike.

Fears grew on Friday 28 August that work could halt across the industry in the world's top producer of the precious metal when workers at Anglo Platinum (AMSJ.J) also rejected a pay offer.

South Africa produces four-fifths of the world's platinum, which is mostly used in making catalytic converters to cut pollutants from car exhausts, and in jewellery.

Anglo American Plc's (AAL.L) unit Angloplat supplies close to half of world platinum and Impala Platinum (Implats) 25 percent.

Some 20,000 workers at Implats have been on strike since last week Monday 24 August at Rustenburg, and some workers at its Marula mine, which employs 4,000, did not show up for work.

The NUM said workers were prepared to stay away for weeks or months.

(Reporting by Agnieszka Flak; Editing by Keiron Henderson)