Vietnamese conglomerate Vingroup expects to launch about 24 shopping centers across the country this year, a leap from the six it has now and its biggest bet so far on the growing spending power of middle class consumers.

The company told Reuters via email that its subsidiary Vincom Retail plans to expand into 19 provinces and cities, covering roughly a third of the country, from three cities now.

Vingroup did not disclose the cost of the expansion, but said it was aimed at tapping Vietnam's consumer growth prospects. Retail and consumer services sales grew 6.3 percent last year to 2.945 trillion dong ($138.2 million), outpacing the 5.6 percent growth in 2013, according to official data.

The retail expansion comes as foreign players enter the Vietnamese market, including South Korea's Lotte, Japan's Aeon and Thailand's Robinson Department Store Pcl.

Vietnam has a 90 million population and the size of its middle class is expected to double by 2020, owing to annual economic growth of over 5 percent since 2000.

According to a 2014 report by property consultancy Frank Knight, the Southeast Asian country also has the world's fastest-growing number of super-rich, with Vietnamese holding net assets of $30 million projected to swell to 293 from 110 in a decade.

Vingroup is one of Vietnam's fastest-growing firms, with a market capitalization of $3.2 billion and interests that include private hospitals, entertainment, education, supermarkets alongside its primary real estate business. Its retail arm had total assets worth $1.7 billion last year.