Antonio, who established the Philippine-China Business Council when he served as a special envoy to Beijing in 2005, says he sees no conflict between his public role and private partnership.

“My role is to enlarge the relationship between the two countries,” he said. Of his business tie to Trump, he said: “I guess it would be an asset.”

Antonio said that he visited Trump Tower in New York days after the US election; he didn’t speak to the president-elect, Antonio said, but he saw Trump talking with potential appointees. Asked about his account, Hope Hicks, a Trump spokeswoman said: “They did not meet.”

Regardless, Antonio’s dual roles as private business partner and official government envoy underscore the global scale of the potential conflicts facing Trump and his family even before he’s sworn in as the 45th president. Questions have been raised in two instances: Trump took a break from transition discussions to meet with three business partners who are building Trump-branded towers in India, according to media reports. And a spokesman for Argentine President Mauricio Macri on Monday denied a report in La Nacion newspaper that Trump had asked for help with permits for a Buenos Aires real estate project during a post-election call with Macri.

Trump rejected concerns about his potential conflicts of interest. “Prior to the election it was well known that I have interests in properties all over the world,” he posted on Twitter Monday night. “Only the crooked media makes this a big deal!”

Few laws govern how US presidents must conduct their personal business affairs. Presidents are exempt from the 1978 Ethics in Government Act, an exception crafted out of the belief that presidents shouldn’t have to worry about triggering ethics probes when making hard decisions.

Kellyanne Conway, a top Trump aide, said that while Trump’s widespread business interests mean “we’re in unprecedented times,” he’s getting advice from “various lawyers, accountants and advisers telling him what he can and can’t do. I’m very confident he is not breaking any laws.”

The US Constitution bars government officials, including presidents, from taking payments or gifts from foreign governments or profiting from a company tied to a foreign government – but it’s unlikely that Trump’s arrangement with Antonio would violate that provision, said Robert Kelner, chairman of the election and political law practice at Covington & Burling LLP in Washington.

“Unless the foreign government was passing funds through that company to Donald Trump, I don’t think the emoluments clause would be implicated – it’s extremely remote,” he said.

There’s nothing illegal about Trump interacting with Antonio as a special envoy to the US on trade and economic policy while also being his business partner – but it creates unnecessary complications for US diplomacy, according to Richard Painter, a University of Minnesota law professor who was President George W. Bush’s chief ethics lawyer. The arrangement means that as president, Trump may have to respond to requests from a business partner who has paid him millions, he said.

“We have a president in the Philippines who is clearly volatile,” Painter said of Duterte. “We don’t want a situation where the US president is financially involved with a whole bunch of his supporters. That will have an adverse impact on our policy and our ability to figure out how to deal with Duterte and try to put back together our relationship with the Philippines.”

Some analysts have compared Duterte to Trump, a comparison Duterte rejected.

The Trump Organization’s interests in the Philippines “might do something to smooth relationships” between the two countries, said Joshua Kurlantzick, senior fellow for Southeast Asia at the Council on Foreign Affairs.

Those interests may expand. Antonio said he’s discussing additional projects with the Trump family in the Philippine resort and leisure sector. For now, though, Trump and Antonio are partnered in Trump Tower at Century City in Makati, Manila’s financial district.

At 280 metres, it will be one of the city’s tallest structures. Antonio said the tower will open in the second quarter of 2017; it has already sold all its 250 condo units, he said.

Trump has said he’ll avoid conflicts of interest by having his oldest children, Donald Jnr, Eric and Ivanka, take over the management of his businesses. But ethics specialists have questioned whether that move would be effective in walling off his private interests from his public duties. And his children’s involvement in his transition planning has raised further questions about the plan.

Antonio said that he visited New York days after Trump’s November 8 victory. He said he went to Trump Tower, where he saw the president-elect talking with several “cabinet contenders,” including Michael Flynn, his eventual choice to become national security adviser.

While he didn’t speak directly to the president-elect during that visit, he did talk with members of Trump’s family, Antonio said. Hicks and Trump’s oldest son, Donald Trump Jnr, didn’t respond to email requests for comment, sent after normal business hours Monday, about discussions with family members.

Antonio said he first met Trump in 1990 in New York, introduced by a mutual friend. Their children know each other, he said. Antonio’s 39-year-old son, Robbie, is listed as a resident of Trump Tower New York and is a real estate investor and art collector. A feature in Vanity Fair magazine in 2013 titled “The Museum of Me” detailed how he commissioned a series of portraits of himself by renowned artists, including Julian Schnabel. Robbie Antonio didn’t respond to requests for comment.

Century Properties is known for branding deals with global names, including American socialite Paris Hilton and Versace; it commissioned French designer Philippe Starck to design high-rise developments in Manila. Ivanka Trump markets her jewellery on the company website that promotes the Trump-branded tower. Antonio said he hopes to see one of the Trump children at the opening ceremony for the tower next year.

The company may not be immune from softening in the luxury residential real estate market. Vacancies in luxury apartments in the Makati central business district rose to about 13 per cent in the three months ending September from 9.8 per cent in the second quarter, broker Colliers International estimates. Century’s real estate sales fell to 4.19 billion pesos (US$84 million) in the nine months through September from 6.62 billion a year ago. The decline “is attributable to a significant portion of revenue recognised in 2015 and prior years from completed projects, as well as less pre-sales and less new project launches,” according to Century Properties.

Antonio said owners of the Trump-branded units in Manila are “probably very happy” Trump won the election and that the skyscraper now bears the name of the incoming US president. He hopes Trump will still make time for him once he takes office, Antonio said, but either way he expects to remain close to the rest of the family. “We interact with everyone – Donald, the kids,” he said. “I guess he’ll be very busy now in his new job.”