Starbucks Corp plans to add more than 12,000 new stores globally by 2021, including doubling the number in China to 5,000.

The world's largest coffee company outlined its growth plans at its biennial investor conference in New York on Wednesday.

Seattle-based Starbucks said it continues to expand briskly in existing markets like the US and newer ones like South Korea and China. The global goal of 12,000 new stores would bring its total store base to 37,000, a 48 percent increase from the current level.

Seattle-based Starbucks entered the Chinese mainland in 1999, and at the conference it unveiled a partnership with Tencent Holdings Ltd's WeChat social media platform, China's equivalent of Facebook, to create a social gifting and digital payment system for China on the instant messaging service.

The world's biggest coffee company plans to open at least 1,000 Starbucks Reserve stores, featuring varied brewing methods and artisanal foods created by its new Italian food partner Princi.

The Starbucks Reserve Roastery in Seattle will also serve as a linchpin of the company's strategy. The roastery and tasting room serves as a gateway to the company's upscale approach that includes specialty coffees, food and a dramatic setting to maintain its status as a sought after meeting place.

Belinda Wong, CEO of Starbucks China, said a similar roastery in Shanghai is scheduled to open in late 2017 and will become "an enticing destination in China".

Wong said China it is the fastest-growing international market for the company. Soon Starbucks will have more than 2,500 stores averaging 5 million transactions a week and over 35,000 employees or partners, she said.