Employees at Nokia's mobile handset manufacturing plant in Chennai are protesting and disrupting work, after the company suspended some staff pending an inquiry, the company said on Thursday.
The suspended employees are reported to have committed "acts of serious misconduct," the company said in a statement.
About 1,200 staff have joined the strike since Tuesday after 63 employees were issued suspension notices pending inquiry, a company spokeswoman said in an e-mail.
Nokia has about 8,000 staff at the facility. To counter the impact of the strike on some production lines, Nokia is using its global production network to meet customer demand, the spokeswoman said.
India's manufacturing sector has strong trade unions, unlike the software services and business process outsourcing industries.
Nokia said it is talking with its workforce and hopes that the matter will be resolved quickly.
A local daily, The Times of India, quoted M. Shanmugam, president of Nokia India Pvt. Ltd Employees Progressive Union as saying that the standoff was triggered after a worker was asked to report for a different shift, which he refused to do. After he was suspended, more workers joined to protest against the suspension and they were also suspended, he told the newspaper.
The union claimed that about 2,000 staff were on strike, and production of nearly 100,000 mobile handsets was disrupted following the strike. Nokia does not disclose the production capacity of its facility.