(Adds background, NUM, police checking reported deaths)
JOHANNESBURG, Nov 22 (Reuters) - Harmony Gold said clashes erupted between rival unions at its Kusasalethu mine in South Africa on Thursday, raising concerns that labour unrest was flaring again in Africa's largest economy days after a wave of wildcat strikes ended.
Harmony spokesperson Marian van der Walt said the confrontation at the mine 65 km (40 miles) west of Johannesburg was between the National Union of Mineworkers (NUM) and the smaller Association of Mineworkers and Construction Union. The turf war between the two has been at the root of much of the recent violence in the mining sector.
Police were checking unconfirmed reports that two people had been killed and one injured in the clashes, a police spokeswoman told Reuters.
The last of the wave of illegal strikes that have swept South Africa's gold and platinum mines this year ended a week ago after workers accepted an offer from Anglo American Platinum Ltd, the world's top producer of the precious metal.
But tensions remain between AMCU and the NUM, which has seen its once unrivalled position challenged by the smaller union amid rank and file perceptions that it has grown out of touch with worker needs.
"Our offices at the Harmony mine were attacked after organisers from another union showed up there demanding a meeting and were refused," NUM spokesman Lesiba Seshoka told Reuters.
The strikes over the last few months have cost companies and the economy billions of dollars in lost output and 50 people were killed in the unrest.
The labour strife prompted Moody's and Standard and Poor's to downgrade their South African credit ratings.
Reserve Bank Governor Gill Marcus said on Thursday the labour troubles were undermining the economy's ability to create jobs.
"In the context of a very weak global economy ... the ability to attract investment and improve the country's ratings must be a clear objective," Marcus said, warning the strikes would lead to job losses in a country grappling with unemployment of over 25 percent. (Reporting by Sherilee Lakmidas, Ed Stoddard and Xola Potelwa; Editing by Pascal Fletcher)