No ordinary collection and amassed over three decades by visionary Swiss businessman, Uli Sigg, 66, this definitive assemblage of some 1500 works spans China's watershed and tumultuous recent decades of modernisation, and is conservatively estimated to be worth $167 million.

In a surprise move after years of hard negotiations with several cities around the world, Sigg chose to donate the bulk of his unique collection to an as-yet-unbuilt Hong Kong visual culture museum, Museum Plus (M+).

Emotional Hong Kong art administrators and leaders praised Sigg's "historically" significant art bequest, that would catalyse what has been a long-delayed and troubled dream to realise a leafy, 40-hectare cluster of modernist buildings, museums and theatres on the edge of Victoria harbour.

"It will enable us to strengthen our position as the cultural hub in Asia," said Stephen Lam, Hong Kong's chief secretary and number two official.

Long known as one of the world's most capitalist financial hubs on the south China coast, the former British colony has struggled to evolve a more vibrant and diversified arts scene to match its self-proclaimed stature as Asia's world city.

But as other major regions in Asia compete fiercely for higher-end cultural and arts based tourism including China, South Korea, Japan, Taiwan and Singapore, Sigg's endowment could help galvanise Hong Kong's current strengths which include a major art fair, as well as its booming art and wine auction markets, buoyed by a wave of mainland Chinese millionaires.

One major problem for Hong Kong, before Sigg's gift, had been a struggle to find quality artwork to fill the proposed cluster of museums, exhibitions and performance venues, particularly given the rapidly rising cost of Chinese artwork.

"It would be impossible to now build a collection similar in depth, scope and quality," said Lars Nittve, a former Tate Modern director now spearheading the M+ project who sees it becoming the next Guggenheim Bilbao or Tate Modern; a "game-changing" art space with global appeal.

Sigg said his decision was motivated by a desire to freely showcase what has been called an "encyclopaedic" collection of sometimes edgy and subversive artworks from 350 of China's leading contemporary artists including activist Ai Weiwei, in a city where freedom of expression is more fully enshrined than on mainland China where sensitive art is still heavily censored.

"My expectation is that these limitations (in China) do not exist in this way in Hong Kong," said Sigg, who was also considering donating his works to other Chinese cities and those in Europe. "To me it's very important that a Chinese public can ultimately get access to these works. (There are) still limitations that exist in mainland China for that."

Under the deal, Sigg, a former Swiss ambassador in Beijing, will donate most of his collection, while 47 pieces will be acquired by the M+ for HK$177 million.

His works include those from China's stable of increasingly prominent art luminaries Zhang Xiaogang, Wang Guangyi. On display at the announcement was a brusque wood carving by Wang Keping of a head with a chained neck and muzzled mouth from the 70s.

An architectural design competition for M+ is slated later this year with the artspace expected to open in 2017. Hong Kong authorities have approved HK$21.6 billion in endowments for the West Kowloon Cultural District with a vision of making Hong Kong "an integrated arts and cultural district with world-class arts and cultural facilities".

(Editing by Paul Casciato)

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