At a glitzy show stall for a new residential development in Hong Kong, property agents with loudspeakers are promoting the latest trend in the overcrowded city -- high-end "micro-flats" which still come with an eye-watering price tag.

Hong Kong's poorest residents are used to making their homes in cramped accommodation, but now developers are touting minuscule upmarket apartments to reel in young middle-class buyers.

Although they are part of swish modern complexes, some of the newly-built studio flats measure as little as 16 square metres (177 square feet) and are on sale for HK$1.5 million -- almost $200,000.

Single entrepreneur Mike Ko is typical of the buyers that developers are targeting: aspiring home owners who are priced out of the overheated Hong Kong housing market.

"I'm 33 years old and I really need my own place," says Ko. "Studios are good enough. They're quite hip and cool as well."

Ko currently lives with his parents in public housing and has been saving to buy, but says that current price tags mean he can only afford tiny properties.

"The market is too expensive, so buying a studio flat is a good first step to home ownership," he said.

Agents are selling the pint-sized flats on the basis that the market boom will only continue.

"You want to buy now because prices will just go up," said one agent at the new Mont Vert development in the suburban neighbourhood of Tai Po.

"You are saving, in a sense."

Mont Vert boasts a clubhouse, sea views and surrounding greenery -- but at 16 square metres, its smallest units are only three times larger than cells in Hong Kong's most populous prison.

The main space doubles as both bedroom and living room, with a kitchen and bathroom tucked away in the corners.

Developer Cheung Kong says that 10 percent of the 1,000 apartments on offer are studios, but could not confirm how many of those had been sold.

The development is not yet completed, and -- despite being a massive investment for potential buyers -- there were no show flats, models, or pictures of the interiors of the studio units immediately available.

- 'Inhumane' conditions -

While some prospective buyers are desperate enough to snap up the tiny flats, there are those who are outraged by the conditions Hong Kong residents are having to bear.

"They are not only small, it is repressive. You are paying that much to be living there, it's ridiculous," Kenneth Tong, a spokesman for local NGO "No Flat Slaves" told AFP.

The organisation believes the government is to blame for a lack of affordable homes and being slow to build more public rental housing.

"People have no other choice," says Tong.

There is a "surging need" for cheaper homes in the city, vice-chairman of Hong Kong's pro-democracy Labour Party Fernando Cheung told AFP.

"As a result, you see these very small flats that I think could be described as inhumane if you compare (them)... with units that would be used to house refugees, or even earthquake victims, in other places," Cheung said.

With many larger and pricier flats bought by wealthy mainland Chinese buyers, the smaller homes are targeted at young professionals, university graduates and newly married couples, among others, who are seeking to live independently from their parents and are looking for more reasonable prices, he added.

"It's really mind-boggling to see how the private residential market in Hong Kong has developed to such an extent," Cheung said.

The overcrowded southern Chinese city suffers from a serious housing shortage, with property prices doubling since 2009.

The dearth of new affordable homes has spurred protests and sentiment against the city's big developers.

Now micro-flats are seeking to fill the gap -- though they will remain well outside many househunters' budgets.

Half of the apartments in the new Le Riviera tower project, in a quiet neighbourhood to the east of Hong Kong Island, measure less than 300 square feet and are priced around $HK5 million. But developers say they will attract single "yuppies" and young families.

"A lot of people who have studied overseas and return love this kind of lifestyle," says David Fong, managing director of the tower's private developer Hip Shing Hong.

"In London, even in metropolitan New York, the flat size is both small and old. We are small but beautiful," he added.

Fong says that the apartments offer a "European continental lifestyle", with balconies, and interiors decorated by a group of Spanish designers.

"It's a compromise. Everyone would love to live in much bigger flats if they could afford it," he said.

But campaigner Tong says the demand for tiny apartments is "twisted", a product of the city's entrenched desire for home ownership.

"You lose your dignity even though you have the bricks and mortar," he said.