Vietnam's city centres are unrecognisable from even a decade ago.

"What's the first designer item you ever bought?" I ask 42-year-old Vietnamese tycoon Le Hong Thuy Tien as we cruise through Ho Chi Minh City in her black Bentley.

It has come to this. I have been asking about her childhood during the Vietnam War (or the American War, as it's known here) for the past half an hour. She has politely refused to be drawn. Fawning questions about how filthy rich she is are all I have left.

"That's a great question!" she exclaims, her perfect eyebrows arching with delight. Sadly, it is only half great. The purchase was so many hundreds of Louis Vuitton tote bags, Bulgari watches and Chanel dresses ago that Thuy Tien can't remember.

Whatever the item was, we establish that she most likely bought it in Paris in the mid-1990s. Back then she was a flight attendant for the national carrier Vietnam Airlines. It was such a coveted job at a time when few Vietnamese could travel that she'd chosen it over a fledgling career as a movie starlet.

Today she is the president of a huge trading company, Imex Pan Pacific Group. "I run 25 private equity and venture capital firms that distribute luxury brands and invest in local shopping malls," she says in her girlish, slightly Americanised English.

Unlike some of Vietnam's super-rich, who are reluctant to flaunt their success in a country run by an increasingly jittery and repressive communist regime, Thuy Tien is all about the money. Her mission, she adds, is to generate annual revenue of US$1 billion ($1.2 billion). How close is she? "I'm over halfway there."

Welcome to modern Vietnam - one side of it, at least - where the pinnacle of achievement is to snare the exclusive rights to distribute Burberry or (Thuy Tien's newest acquisition) the franchise for Dunkin' Donuts. The city formerly known as Saigon was renamed Ho Chi Minh City to celebrate national unity after two decades of civil strife, including the war with America from 1965-75. Now it is Vietnam's commercial hub.

Gleaming billboards and five-star hotels signal the country's status as Asia's fastest-growing economy after China. Since liberalisation began in the 1980s, founding father Ho's Communist mantra "Success, Success, Great Success" has become the creed of hardcore capitalism.

Up to three million Vietnamese died in the war, many of them male soldiers who left wives and young children (although women fought and died, too). When the war ended, failed collectivisation policies plunged the country into dire hardship. Single mothers supported their families with clandestine household commerce and raised their daughters to be equally resourceful. Today, female entrepreneurs own about 25 per cent of all private enterprises in Vietnam, mostly small family outfits.

"Women? Oh, they run this country underneath it all," Frenchman Yves-Victor Liccioni, a luxury-brand PR guru and longtime resident, tells me one evening under a canopy of fairylights at one of the city's relaxed European bistros.

"They're powerful, energetic and they love making money."

It takes 40 minutes to reach Thuy Tien's home overlooking the swampy Saigon River. She lives here with her husband, two teenage children and 10 pyjama-clad housemaids. It is a typical new-money neoclassical mansion: giant gates with ornate gold metalwork, white exterior, Doric columns.

In the grounds there are statues of lions standing sentry, cherubs keeping watch, and horses and dragons apparently loitering for the fun of it. There's a swimming pool, a tennis court and a garage housing three varieties of Rolls-Royce, another Bentley and an SUV. "My husband collects cars," Thuy Tien explains casually.

We go inside. It is no surprise that Thuy Tien likes gold - there is nobody in Vietnam who doesn't - but it seems infeasible for one person to like so much of it. She designed the decor. Everything is so gold it is easier to describe what isn't gold, including a white marble staircase hewn from rock from the coastal city of Da Nang. "This pure-white marble is very rare," boasts Thuy Tien. "We mined it ourselves."

Thuy Tien is married to a Vietnamese-born, Philippines-raised airline tycoon whom she met during her flight-attendant days. He is the brains behind state-owned Vietnam Airlines' international expansion, and his ties to the ruling elite have almost certainly proved helpful to his wife along the way. Nevertheless, Thuy Tien insists her financial success is her own.

"I studied every aspect of business from A to Z so I could compete at the highest level."

Relaxing on her gilded sofa, she opens up a little about her past. She was born in the capital Hanoi in 1970. Her father died when she was 5, just before the war ended. (She won't say whether he was a soldier or which side her family was aligned with.) "My mother raised me and my five siblings alone. She was a schoolteacher and very strict. She taught us that working hard was the key to survival."

It's a lesson she says she has never forgotten, and it is true that few women in Vietnam who are hitched to wealthy men are content to be trophy wives. Shortly after she married, Thuy Tien fought for and won a lucrative contract to open Vietnam's first supermarket in 1995. "It was a joint venture with the military. I sat in meetings with all these men in uniform and they didn't believe a 25-year-old woman could handle 20,000 products. I was determined to prove them wrong." She did. The supermarket was mobbed on its opening day.

Thuy Tien attributes her huge success since to her knack for understanding what "modern Vietnamese consumers want". Her company is now the exclusive agent for luxury brands such as Ferragamo, Ralph Lauren, Rolex and Bulgari.

The Government is in a dangerous bind. Increasingly unable to sustain its Communist edifice alongside runaway capitalism, it has been ruthlessly cracking down on dissent. At least 22 democracy activists and bloggers were imprisoned last year. But the super-rich are not safe, either. Tales of the wealthy quaffing champagne infused with 22-carat gold, eating the brains of live monkeys as a delicacy and buying diamond-encrusted mobile phones have irritated the public.

In a show of tackling corruption, the regime has recently arrested several top executives at state-owned enterprises for "mismanaging funds". The blood of business magnates all over the country has run cold.

Vietnam's city centres are unrecognisable from even a decade ago. Ho Chi Minh City is full of women carrying "It" bags and doing valiant battle with the uneven pavements in £400 ($714) Jimmy Choos. Fake noses and eyelids are all the rage. Predictably, cosmetic surgery has been taking off among both sexes as Vietnamese society has grown more image conscious. Liccioni divulges that most people fly to Thailand or Singapore for big operations, and that top French dermatologists fly to Vietnam to hold "Botox bootcamps". "They come here for three weeks at a time and do nonstop injections and treatments. "It's very lucrative."

Restaurant owner Hang Dang admits she's had "a few injections". But she insists she has no time for the conspicuous consumption of other home-grown multimillionaires.

"I'm a practical person. I like what I like."

• 90 Million population.
• 150 Per cent rise in multimillionaires in the past five years alone.
• 60 Per cent of Vietnam lived in poverty 20 years ago. Now it is 20 per cent.

- Observer