BEIJING, May 18 (Xinhua) -- The constant widening of opening up in China's manufacturing sector will not only help domestic industrial upgrading but benefit all foreign companies, industry experts say.

"The manufacturing sector has consistently expanded the fields and raised the level of opening up," said Huang Qunhui, head of the industrial economics institute under the Chinese Academy of Social Sciences.

Among 609 sub-categories of the manufacturing sector, 96.1 percent were completely open to foreign investment, according to the Ministry of Industry and Information Technology (MIIT).

In 2017, the manufacturing sector attracted total foreign direct investment of 33.5 billion U.S. dollars, while outbound investment by domestic companies in the sector totaled 120.1 billion dollars.

The MIIT data also showed that 4,986 foreign-invested manufacturing firms were set up last year, up 24.3 percent year on year. The main fields of foreign investment covered computers, integrated circuits, smart manufacturing and other high-tech sectors.

The sector's open attitude towards foreign investment "not only raised the country's own strength, but also provided handsome returns for foreign companies and institutions," Huang said.

Last month, China announced plans to open the automobile sector wider to foreign investment, with a timetable to phase out the shareholding limits for foreign investors.

Shareholding limits for special-purpose vehicles and new energy vehicles will be scrapped for foreign investors in 2018, while those for commercial vehicles will be lifted in 2020, according to the National Development and Reform Commission, the country's top economic planner.

MIIT chief engineer Chen Yin said the ministry has been working with other departments on reducing automobile import tariffs "by a considerable amount," and would make the cuts public as soon as possible.

Opening up the automobile sector to foreign firms put an end to a "protection period" for domestic brands, said Dong Yang, vice director of the China Association of Automobile Manufacturers.

"Instead of having huge impact on domestic automakers, wider opening up will be conducive to encouraging competition and pushing the industry to raise quality and efficiency," Dong said.

Industrial development depends hugely on global economic integration, said MIIT chief engineer Chen Yin.

"The Chinese manufacturing sector will further expand opening up to stimulate the innovation of advanced technology, realize compliance with international economic and trade rules, and offer more and better investment opportunities to foreign firms," Chen said.

Minister of Industry and Information Technology Miao Wei said that while continuing to uphold its stance on introducing foreign investment, the government also encouraged Chinese manufacturers to invest overseas.

By the end of last year, Chinese companies had invested more than 30 billion dollars in overseas economic and trade cooperation zones, creating 258,000 local jobs.

"A pattern of all-round opening up of the manufacturing sector has come into being," Miao said. "The fundamental principle for China's manufacturing development was, is and will always be pursuing mutual benefits through open cooperation."

"China will continue to raise policy transparency and stability, optimize government services and improve the business environment for investors from all around the globe," he said.