Blockchain electronic invoices issued in China's tech hub Shenzhen have exceeded 10 million in number as the city promotes e-billing, the Shenzhen Tax Service said Thursday.

More than 7,600 companies have accessed Shenzhen's blockchain electronic invoice system to date, with an aggregate invoice amount of more than 7 billion yuan (about 1 billion U.S. dollars).

Blockchain invoices have been widely used in finance and insurance, retailing, hotel catering and parking services in Shenzhen since the city issued its first blockchain electronic invoice in August 2018.