Brisbane is leading the nation in reducing the number of coffee cups that end up in landfill, with the River City having the highest number of businesses registered with Responsible Cafes.

Cafes sign up with the organisation for free and are encouraged to offer an incentive, such as a discount, free upgrade or complimentary treat, to customers who bring their own reusable cups.

War on Waste presenter Craig Reucassel with a Melbourne tram stuffed with more than 50,000 takeaway coffee cups - representing what Australians send to landfill every half-hour.

Responsible Cafes operations manager Rachel Draper said the organisation had started in 2013 but gained momentum after featuring on the ABC's War on Waste documentary series last year.

The number of cafes involved nationally jumped from about 400 before the program aired to about 3750 this year.