A sorting centre of Zhongtong (ZTO) Express ahead of the Singles' Day shopping festival, Chaoyang District, Beijing, on Sunday. REUTERS/Jason Lee Transactions on Alibaba have passed $9 billion (£5.9 billion) in the first 12 hours of Singles' Day, passing the mark from last year with half the day still to go.

More than $1 billion (£659 million) was bought within the first eight minutes, and the site saw $3.9 billion (£2.5 billion) in sales in the first hour.

Sales on Singles' Day in 2014 were $9 billion, up from $5.8 billion (£3.8 billion) the year before.

Alibaba alone is expecting to ship 20 million parcels from this year's sales.

Singles' Day is an annual event held on November 11 as a response to Valentine's Day. It is billed as a time for a celebration of single life.

Alibaba became involved in 2009 when then-CEO Daniel Zhang came up with the idea to cut prices on the bachelor's day. It has since become the biggest 24-hour shopping period in the world, spreading to more than 400,000 outlets. Many of these outlets receive more orders in one day than they would in a month.

An employee working at a Tmall logistic centre in Suzhou, Jiangsu province, China, on October 28. REUTERS/Aly Song

Total sales for Alibaba this year are projected to top $14 billion (£9.2 billion).

The day far eclipses the $5.6 billion (£3.6 billion) spent by Americans on Black Friday and Cyber Monday combined.