The 27-year-old grew up in Otara and although she says her family always made sure the children had presents, she knew many of her friends went without.
"I'll always remember one Christmas. Our family was out on the front yard with our remote-control cars and stuff and our friends were looking at us playing.
"We asked them: 'Oh, what did you guys get?' They said: 'Nothing'. I'll never forget that feeling and the look on their faces."
Ms Fa'asoa - mother to 3-year-old daughter Hope and 2-year-old son MJ Tito - has made it a tradition in their family for each member to buy a gift for someone to go under the Christmas tree at their local store.
She also organises events and activities at schools and local companies to raise awareness of the appeal. "I want my kids to grow up knowing that Christmas isn't always about yourself - but about being able to help somebody else.
"Now whenever we walk past a big Christmas tree in the mall, my kids point to it and say: 'Hey mum, remember when we gave a present for someone last year?' That feels good."
The Kmart Wishing Tree appeal has been going for the past 20 years and is in partnership with the Salvation Army. Last year, more than 15,000 families received gifts through the campaign.
The Army's secretary for social services, Major Pam Waugh, said many families were put under huge strain during the holiday season.
"Our last quarter to September 30 saw 4000 new families or individuals seeking assistance nationally for food parcels. Many others also sought help for the first time with budgeting, counselling, furniture and clothing."
Major Waugh said donations enabled all families to get a few extra items to enjoy over Christmas.
