Jennifer Lawrence has given her brother's charity work a boost by donating a trip to Belize to an auction raising funds for a 12-month-old leukaemia survivor.

The Hunger Games star visited Kosair Children's Hospital in her hometown of Louisville, Kentucky in December (13) and spent time with sick kids, including Hadley Mercer, who was diagnosed with leukaemia when she was six months old.

The actress has now donated signed movie memorabilia and a trip to Belize to an auction organised by her brother, Ben Lawrence, to help the little girl.

The auction is part of a fundraising street party event which will take place in Louisville on Saturday (21Jun14).

Ben tells, "She (Jennifer) actually got that (trip) in her Oscar swag bag a few years ago and ended up going down there and developing a relationship with the guy who owns the island and it's heaven on earth."

Lawrence used her friendship with the owner to arrange a trip for the winning bidder. She has also donated signed items from her films The Hunger Games and American Hustle. All proceeds from the auction and the street party will go to the Mercer family to help cover medical bills.

Mercer has been declared cancer-free but is still in hospital following complications from her bone marrow transplant in April (14).