Every Citi cardholder who signs up for online account management, Internet bill payments and paperless statements will be automatically entered into the sweepstakes. Customers that submit payments and perform balance consolidation online will also have a chance of winning one of the prizes.

The sweepstakes winner will be given the choice of a hybrid car or green home makeover. Other prizes include trips to an eco lodge in Costa Rica and a year's supply of organic, sustainably-harvested coffee.

The bank says it will also plant a tree for every customer that signs up for paperless statements in April and May. Citi has planted 1.2 million trees since it launched the programme last year.

Commenting on the latest initiative, Rob Rosenblatt, executive vice president, Citi Cards, says: "By switching to paperless online services, we are able to offer a green option that's both effective and meets the needs of our customers."

Last year Citi announced plans to spend EUR170 million to build one of the "greenest" data centres in the world in Frankfurt as part of its $50 billion climate change programme. The bank aims to cut greenhouse gas emissions by 10% at 14,500 facilities worldwide by 2011.