Starbucks South Korea says the number of customers bringing their own cups to the store leapt 24 per cent in just one month.

The boost is the result of its ‘Eco Bonus Star Program’ aimed at reducing waste and improving consumer awareness of sustainability issues.

Through the Eco Bonus Star Program, customers of Starbucks South Korea can collect additional ‘stars’ – or bonus points – by bringing their own cups to cafes. The stars can be used for discounts and other benefits.

Customers can choose to receive an immediate discount of 300 won (US27 cents) if they don’t want to collect stars.

Starbucks said that, compared to 970,000 customers who brought their own cups in October, more than 1.21 million customers brought their own cups in December, the first full month of the program.

Two-thirds of customers chose to save up stars, rather than receive the discount.

“More than 1.81 million additional stars were given to customers just 50 days after the Eco Bonus Star program was implemented,” said Starbucks.

“Gold members for My Starbucks can get a free drink for 12 stars, which also likely encouraged more customers to bring their own cups.”

More than 8 million customers have brought their own cups this year, twice as many as last year.

* Original reporting by Korea Bizwire.