(Bloomberg) -- Citigroup is targeting a 10% increase in its Asian wealth assets under management this year as the region's growth creates more millionaires.

The trend of an "expanding middle-class and increasing concentration of wealth among affluent individuals in Asia is very much alive and continuing," Jonathan Larsen, Asia-Pacific head of consumer banking, said in an interview in Hong Kong last week. A 10% gain would match last year's growth.

Citigroup made 20% of its revenue in Asia last year and manages $250 billion of assets for wealth management clients in the region. In Hong Kong, the bank is trying to double within three years the number of clients using the Citigold Private Client service, for people with $1 million to $10 million of assets. Larsen didn't give the current number using it.

At least 56,000 people in Hong Kong hold more than HK$10 million ($1.3 million) in liquid assets, Citigroup estimated in a March study. The city's population is 7.3 million.

Citigroup will add to the more than 3,000 staff in Asia who deal with clients, such as relationship managers and portfolio counselors, as the assets under management grow, Larsen said. The Citigold Private Client service contributes 40% of the firm's Asian wealth management revenue and is expanding in countries such as China and India, Larsen said.

On the outlook for the bank globally, Larsen said Citigroup is "optimistic" because of an improving U.S. economy and signs that Asian economies will continue to outpace growth in the rest of the world.

The firm's push into digital banking services will help the wealth business expand without the cost of setting up branches, he said. The 7.5 million customers using Citigroup's online and mobile-banking services in the region will probably grow to 15 million by 2019, bolstered by rising affluence and a burgeoning middle class, Larsen said in an earlier interview.

Alfred Liu is a reporter with Bloomberg News.

Read more: