HONG KONG (BLOOMBERG) - A Hong Kong apartment sold for HK$640 million (S$111 million), making it Asia's most expensive per square foot in a further sign of buoyancy in the city's upscale housing market.

Wharf Holdings and Nan Fung Development sold an apartment at Mount Nicholson, one of the most iconic upscale projects in the city, for HK$140,800 per sq ft, according to the companies.

The apartment on the Peak, a luxury residential area on Hong Kong Island, came with three parking spaces and is measured at 4,544 sq ft.

That broke the record set by CK Asset Holdings' 21 Borrett Road project almost nine months ago. Hong Kong tycoon Victor Li's firm sold the apartment for HK$136,000 per sq ft in February.

The most recent purchase underscores how the city's luxury residential market - already one of the world's priciest - continues to grind higher.

Total transactions in the 12 months through June came in at HK$12.8 billion, more than double the amount a year earlier, according to Colliers International.

Prices for upscale homes will grow 3 per cent in the second half of the year, driven by robust demand from both mainland Chinese and wealthy local residents, Colliers estimated.

The unidentified buyer at Mount Nicholson also bought an adjacent apartment for HK$561 million, boosting the total bill to more than HK$1.2 billion for the transaction, the developers said.

Mount Nicholson is one of the most sought-after ultra-luxury developments among Hong Kong's wealthy.

Given the scarcity of land on the Peak, it is rare to have new projects available for sale in the exclusive neighbourhood.

Buyers include the late tycoon Stanley Ho's daughters Alice Ho and Sabrina Ho, as well as Mr Edwin Leong, founder of local developer Tai Hung Fai Enterprises.

A unit in Mount Nicholson had claimed the record for Asia's most expensive apartment in 2017 before 21 Borrett Road replaced it earlier this year.