Yamato Holdings Co., Asia’s biggest package-shipping company, is looking for partners to start a chilled delivery service in Vietnam and Thailand as demand grows for sushi and other Japanese cuisine, according to people familiar with the plan. The company, which pioneered the business in Japan, wants to start ventures to provide services to restaurants and small businesses in the next few years, two people said, asking not to be identified because the details haven’t been firmed up yet. It may also decide to start the business alone, they said. Yamato is expanding its operations overseas as it targets a growing middle-class in Southeast Asia, while the population shrinks in its home country of Japan. The company, which started the world’s first home cold delivery system in Japan in 1988, is the biggest provider of the service in the country and has already started the service in Singapore, Hong Kong, Malaysia, China and Taiwan. Hiroyuki Yamamoto, a spokesman for Yamato, said no decision has been taken yet on the expansion. The Tokyo-based company is adding partners in distribution overseas and agreed to take a stake in Malaysia’s GD Express in January to help grow its logistics business. Yamato got about 2 percent of its sales of 1.4 trillion yen ($14 billion) from overseas in the year ended March, according to the company.