Technology giant Foxconn's plant in Shanxi province has launched a massive recruitment drive for an additional 20,000 workers to meet orders for next-generation smartphones.

The company's industrial park in Taiyuan, Shanxi's capital, currently has a workforce of 51,000. The extra workers are needed for new production lines in which it has invested 3.2 billion yuan ($520 million), said a human resources executive who declined to be named.

He said the company has to recruit as many workers as possible because production is expected to continue expanding until 2016.

Foxconn is the world's largest contract electronics maker, and it assembles products for top international brands such as Apple, Sony and Nokia.

The company has other smartphone production bases in Zhengzhou, Henan province, and Shenzhen, Guangdong province.

The HR executive said that although Foxconn is eager to use robots in place of workers, people are essential in many areas, such as quality testing and polishing.

The Shanxi plant exported 5.96 million mobile phones last year, earning $1.18 billion, according to the provincial Bureau of Commerce.

Foxconn, which has an estimated 1.2 million employees on the mainland, has come under fire in recent years after suicides and labor unrest at its plants were exposed.

In 2010, at least 13 Foxconn employees died in apparent suicides, which activists blamed on tough and high-pressure working conditions, prompting calls for better treatment of workers.

Apple is set to unveil the iPhone 6 on Sept 9, and industry insiders believe Foxconn's plants on the mainland will need to recruit more than 100,000 workers this year to keep up with demand.

Foxconn recruiters have been distributing leaflets to attract migrant workers at railway terminals in labor-rich inland provinces.

Xinhua in Taiyuan