The Giving Tree was set up at Trafalgar Square on Monday and Salvation Army people will be on hand to explain how it works.
"The tree sits on a table, and when people come up to the tree we're just going to offer them [a bootie], choose one if you want it, they'll be given out like that, just in exchange or as an acknowledgement."
They will also be giving out colouring-in competitions to children.
"And we've got some little gingerbread men as well."
To donate to the Giving Tree, people can either buy and give gifts, or they can donate money or Christmas food.
The Giving Tree will be outside Countdown at Trafalgar Square until Saturday between 10 and 2pm.
On Saturday a Salvation Army choral group will be in Trafalgar Square, entertaining shoppers and bringing Christmas cheer. The Salvation Army mascot, 'Shieldy', will be part of the entertainment.
Other collection points for donated gifts, food or money will be at the Family Store in Victoria Ave and the Salvation Army Church office at 4 Indus St. If mobility is a problem, call the Salvation Army on 021 955 293 to arrange collection.