Apple has placed Wistron on probation, saying on Saturday it would not award the Taiwanese contract manufacturer new business until it addressed the way workers were treated at its southern India plant.

Contract workers angry over unpaid wages destroyed property, gear and iPhones on Dec. 12, causing millions of dollars in losses to Wistron and forcing it to shut the plant.

In a statement to the Taiwan Stock Exchange, Wistron said its consistent policy was not to comment on its business relations with customers.

Wistron shares fell about 3% in early trade, underperforming the broader market.

The company has been cooperating with the local government investigation into what happened and "will cooperate with customers on carrying out the improvement and restoration of work plan", Wistron said.

"As the Narasapura factory is a new production line, at present its output is limited, and the initial estimate is that there is no major impact on the company's finances and business."

Wistron on Saturday admitted some workers at the plant in Narasapura in Karnataka state had not been paid properly or on time, and said it was removing a top executive overseeing its India business.

Apple said it will continue to monitor Wistron's progress on corrective action.

(Reporting by Ben Blanchard; Editing by Sam Holmes)