SANTIAGO (Reuters) - Walmart Chile's workers union launched a strike on Wednesday, days after negotiations for a new collective bargaining agreement failed, the union said in a statement.

The National Federation of Walmart Workers had last week warned of the strike action, saying the local branch of retail giant Walmart ( WMT ) "had not been negotiating since the start of the process".

Union leader Karen Gonzalez told Reuters that on Tuesday, the last day of negotiations, the union had requested a five-day extension but the company gave a "resounding no."

"We managed to close many stores, close to 100 are not selling goods right now because of the workers' demonstration," she added.

Walmart Chile did not immediately respond to a request for comment.

The strike began at midnight and involves over 14,000 workers, affecting stores run by Walmart Chile, which include the popular Lider supermarket chain.

In a statement on the union's Facebook page, workers invited customers to shop instead at local stores.