The company produces circuit boards for smartphones and tablets and supplies firms such as Apple and Intel as well as major European auto suppliers.

It cut its 2019/20 revenue forecast by around 7% to 960 million euros (814.82 million pounds), saying production in China was affected by the spread of the coronavirus.

"We have to manage things on a day-to-day basis with regard to the coronavirus," CEO Andreas Gerstenmayer told Reuters.

"With regard to the strategic possibilities we see in the market, nothing has changed ...we actually have the best chances and are also well positioned."

The company lowered its forecast for 2019/20 margin on earnings before interest, tax, depreciation and amortisation (EBITDA) to 18%-20% from 20%-25%.

However, it remained upbeat on the medium term outlook, betting on strong growth potential in new applications for smartphones and wearables and in increasing demand for high-performance microprocessors.

The group employs nearly 7,000 staff in China, where it operates one plant in Shanghai and two in the city of Chongqing, around 900 kilometres from the city of Wuhan, where the coronavirus outbreak began.

The Shanghai site and one Chongqing plant must remain closed until Feb 10, the CEO said. The second Chongqing plant was allowed to continue production at reduced capacity.

There is enough raw material in Chongqin to continue production for another two to three weeks, he said.

Various provinces and cities in China have called for factories to halt work to help stop the spread of the virus.

Technology firms that have maintained operations to manufacture parts and products include Huawei Technologies and Semiconductor Manufacturing International Corp (SMIC).

The new virus has already killed over 420 people, most of them in China. The number of confirmed cases in China has risen above 20,000.

Once the restrictions are lifted, Gerstenmayer expects supply chains within China to stabilise within two weeks in a best case scenario.

AT&S reported a 29% drop in core profit to 156.4 million euros for the nine months through December citing high investment in research and development and a tough market.

However, it confirmed its medium-term guidance and still expects revenue to hit 2 billion euros on a compound annual growth rate of roughly 15% in the next five years.

By Kirsti Knolle