The proportion of total transactions made via smartphone app continues on an upward trajectory for Starbucks.

Mobile transactions now account for 14 per cent of in-store sales in the US, with five million payments made via mobile device every week.

The figure is up from a 10 per cent figure published by the company in July 2013.

The coffee chain also plans to trial mobile ordering via its app, said Adam Brotman (pictured), chief digital officer. These plans have been previously revealed.

Brotman was speaking at the company’s annual investor meeting.

Having a mobile strategy is viewed by analysts as increasingly significant for coffee chains and fast-food restaurants.

“Mobile is very important,” Peter Saleh of the Telsey Advisory Group told Bloomberg. “The companies that are taking share are the companies that have some mobile, digital platform — Papa John’s, Domino’s, Starbucks, Dunkin’.”