Production of the Apple iPhone 12 (AAPL.O) at a Foxconn (2317.TW) factory in India has slumped by more than 50% because workers infected with COVID-19 have had to leave their posts, two sources told Reuters.

More than 100 Foxconn employees in the state have tested positive for COVID-19 and the company has enforced a no-entry ban at its factory in the capital of Chennai until late May, one of the sources said.

Taipei-based Foxconn, the world's largest contract electronics maker and a major supplier to Apple, said a small number of employees at one of its facilities in India tested positive for COVID-19 and the company was providing them with support, including medical assistance.

"Foxconn places the health and safety of our employees as our highest priority and that is why we have been working closely with local government and public health authorities in India to address the challenges that we and all companies are facing in dealing with the COVID-19 crisis," it said in a statement to Reuters.

Market research firm Canalys said that growth in India extended through the first quarter, with Apple shipping more than a million iPhones.

However, the outlook has been dimmed by the coronavirus crisis engulfing India, where COVID-19 cases and deaths have surged at a record pace in recent weeks.

Nokia and Chinese smartphone maker OPPO last year suspended production at factories in India after workers tested positive for COVID-19.

Taipei-based tech research firm TrendForce on Monday trimmed its global smartphone production growth forecast to 8.5% from 9.4%, citing the coronavirus impact in India on major vendors including Samsung (005930.KS) and Apple.