The trademarks pave the way for branded spas, massage parlours, golf clubs, hotels and even private bodyguard and escort services across China.

President Trump has said he will not conduct new foreign deals while in office.

And in China, it is common to register trademarks defensively, as a way to prevent trademark squatting.

All the marks were applied for in April 2016, while Mr Trump was campaigning.

If no one objects, they will be formally registered after 90 days. All but three are in the president's own name.

If President Trump receives any special treatment in securing trademark rights, it would violate the US Constitution, which bans public servants from accepting anything of value from foreign governments unless approved by Congress, ethics lawyers from across the political spectrum say.

Concerns about potential conflicts of interest are particularly sharp in China, where the courts and bureaucracy are designed to reflect the will of the ruling Communist Party.

Dan Plane, a director at Simone IP Services - a Hong Kong intellectual property consultancy, said he had never seen so many applications approved so quickly.

"For all these marks to sail through so quickly and cleanly, with no similar marks, no identical marks, no issues with specifications - boy, it's weird," he said.

The trademarks are for businesses including branded spas, massage parlours, golf clubs, hotels, insurance, finance and real estate companies, retail shops, restaurants, bars, and private bodyguard and escort services.

Spring Chang, a founding partner at Chang Tsi & Partners, a Beijing law firm that has represented the Trump Organisation, declined to comment specifically on Mr Trump's trademarks.

But she did say that she advises clients to take out marks defensively, even in categories or subcategories of goods and services they may not aim to develop.

"I don't see any special treatment to the cases of my clients so far," she added.

"I think they're very fair and the examination standard is very equal for every applicant."

Richard Painter, who served as chief ethics lawyer for President George W Bush, said the volume of new approvals raised red flags.

"A routine trademark, patent or copyright from a foreign government is likely not an unconstitutional emolument, but with so many trademarks being granted over such a short time period, the question arises as to whether there is an accommodation in at least some of them," he said.

Mr Painter is involved in a lawsuit alleging that Mr Trump's foreign business ties violate the US Constitution.

President Trump has dismissed the lawsuit as "totally without merit".

China's State Administration for Industry and Commerce, which oversees the Trademark Office, and Trump Organisation general counsel Alan Garten did not immediately respond to requests for comment.