SANTIAGO, Aug 14 (Reuters) - Lider, Wal-Mart Stores Inc's main supermarket chain in Chile, has signed a new work contract with its employees, averting a possible strike, the union said on Monday.

After weeks of negotiations, the 16,500-member Lider Inter-Company Union (SIL) voted to accept the company's latest offer. While the workers had voted to walk off in late July, they kept working while union leaders and company representatives attempted to negotiate a deal.

"The document ... is expected to be signed on Wednesday," SIL said in a statement.

Walmart Chile, Wal-Mart's Chile subsidiary, operates 380 stores in the South American country, largely under the Lider brand.

The company could not immediately be reached for comment. (Reporting by Felipe Iturrieta; Writing by Gram Slattery; Editing by Sandra Maler)