Sotheby's auction house said on Monday it would launch regular wine sales in Hong Kong this April, but the economic downturn was set to put a damper on prices despite expectations of solid Asian demand.

The single-owner sale will include some 9,000 bottles of fine vintages from the cellars of a top American wine collector, but the auction house said the seller wanted to remain anonymous.

The auction will be held in two parts, in New York on March 14th and Hong Kong on April 4th. The Hong Kong sale will be the larger of the two with $3 million worth of wine expected to be sold and another $2 million in New York.

"We believe the wines will sell here as well, or better than, they would in New York," Jamie Ritchie, Sotheby's head of wine in North America, told Reuters.

Ritchie said he hoped the wine's solid provenance from a renowned collector would help bolster the sale, though prices and estimates would likely remain depressed for now.

"We've obviously adjusted all the estimates to correspond with the current market conditions, so estimates have been brought down somewhere between 25 and 40 percent," he added.

"We have no expectations that they're (wine prices) going to be anything like they were in May of last year."

The 9,000-bottle sale will comprise Bordeaux wines including those from top chateaux like Margaux, Lafite, Petrus and Mouton Rothschild.

Some 1,500 bottles of Domaine de la Romanee-Conti will also be sold, although the celebrated wine has been among the hardest hit recently, with prices plunging some 70 percent since 2007.

Hong Kong is positioning itself as Asia's main wine hub following the abolition of wine duties last year.

Wine auctions in the city by rivals such as Bonhams and Acker Merrall & Condit in the first half of last year achieved record results, before demand eased off in the second half.

Rival auction house Christie's, however, hammered off $4 million of wine at a Hong Kong in late November, including rare vintages sourced direct from Chateau Latour's reserve cellars.