A Hong Kong tycoon has placed the biggest ever order for Rolls-Royce cars, agreeing to buy 30 Phantoms to chauffeur guests at a luxury resort he is building in Macau.

Stephen Hung's $20m (£12m) purchase surpasses the 14 Phantoms bought by Hong Kong's Peninsula hotel in 2006.

Hung signed the deal with Rolls-Royce executives on Tuesday at the company's Goodwood factory in England.

The extended wheelbase Phantoms will be used for guests at Hung's "ultra-luxury" Louis XIII hotel, which is scheduled to open in early 2016.

Rolls-Royce said two of the cars will be the most expensive Phantoms ever commissioned, complete with gold-plated accents on both the exterior and interior.

Louis XIII Holdings said it would pay the carmaker a $2m deposit, $3m more by the end of the year and the remaining $15m when the cars are delivered in the first half of 2016.

The Phantom's list price is about $600,000, but many buyers order custom features that push prices much higher. Customers have been known to spend more than $1m on bespoke models.

With casino revenues of $45m last year, Macau is the world's most lucrative gambling market, outpacing Las Vegas seven times over. After authorities ended a casino monopoly a decade ago, newly wealthy gamblers from mainland China started pouring in to glitzy new resorts built by foreign operators such as Las Vegas Sands and Wynn Resorts.

The boom, however, is beginning to fade as the Chinese president Xi Jinping's 's corruption crackdown starts to bite, putting a dampener on lavish spending by China's wealthy.

Macau's gambling revenues fell 6% in August, the third straight month of annual decline after five years of uninterrupted growth.

Hung, a former investment banker, is known for his flamboyant style and the resort looks to be the flashiest of the wave of expansion projects now under construction in the tiny Chinese territory near Hong Kong.

The resort will boast a 1,860-sq metre (20,000-sq ft) villa billed as the world's "most extravagant" hotel suite, which will reportedly cost $130,000 a night.

Hung has even enlisted a descendent of Louis XIII to help with the hotel's design, based on French Renaissance and Baroque styling.