The United States and China were poised to escalate their trade war on Thursday, with both sides set to implement punitive 25 per cent tariffs on $16 billion worth of the other's goods.

The latest round brings to $50 billion the value of imports subjected to tariffs on either side since early July, and more are in the pipeline, adding to risks for global economic growth.

Washington will hold hearings this week on a proposed list of an additional $200 billion worth of Chinese imports to face duties. US Customs and Border Protection confirmed on its website that at 12:01 AM EDT (0401 GMT) on Thursday, which is just past noon in Beijing, it would begin collecting extra 25 per cent duties on 279 Chinese import product categories valued at $16 billion.

China has said its own tariffs on a list of $16 billion worth of imports from the United States would be effective at 12:01 PM local time.

The tariffs were set to take effect amid two days of talks in Washington between mid-level officials from both sides, the first formal negotiations since US Commerce Secretary met with Chinese economic adviser Liu He in Beijing in June.

Business groups expressed hope that the two-day meeting would mark the start of serious negotiations over Chinese trade and economic policy changes demanded by President Donald Trump. However, Trump on Monday told Reuters in an interview that he did not “anticipate much” from the talks led by US Treasury Under Secretary David Malpass and Chinese Commerce Vice Minister Wang Shouwen.

Economists reckon that every $100 billion of imports affected by tariffs would reduce global trade by around 0.5 per cent. They have assumed a direct impact on China’s economic growth in 2018 of 0.1-0.3 percentage points, and somewhat less for the US, but the impact will be bigger next year, along with collateral damage for other countries and companies tied into China's global supply chains.

sweeping changes

Trump has threatened to impose duties on virtually all of the more than $500 billion of Chinese goods exported annually to the United States unless Beijing agrees to sweeping changes to its intellectual property practices, industrial subsidy programmes and tariff structure.

That would more than exceed the size of China's exports to the United States, raising concerns that Beijing could consider other types of retaliation, such as making life more difficult for American firms in China or letting its yuan currency weaken further to keep its exports competitive.

Trump's hard line has rattled Beijing and spurred criticism within Chinese policy circles over its handling of the trade war, sources have said. Beijing has denied US allegations that it systematically forces the unfair transfer of US technology and has said that it adheres to World Trade Organization rules.

Washington's latest tariffs apply to products including semiconductors, plastics, chemicals and railway equipment that the Office of the US Trade Representative has said benefit from Beijing's “Made in China 2025” industrial plan to make China competitive in high-tech industries.

China's list of 333 US product categories hit with duties includes coal, copper scrap, fuel, steel products, buses and medical equipment.