Nadene Lomu is asking that people stop stealing tokens left by her sons on her late husband Jonah's grave.
In an emotional Facebook post, Lomu said "it saddens me that our sons things they choose for you keep being taken off & taken away from yr place of rest".
She said "a child's love is innocent & pure", and said the removal of the tokens from the grave of the legendary All Black rugby player had hurt her two sons.
Nadene's mother Lois Quirk commented on her daughter's Facebook post early on Friday morning, saying "saddens me so much to see my beautiful grandsons working hard putting their decorations of flowers in once again for their Daddy and they keep being taken away".
The post had many comments from friends and family sharing their feelings about the thefts.
One Facebook user commented "I'm numb at this news", while another commented "Don't take from a grave. You end up taking more than flowers away".
Many people offered their condolences to the Lomu family, with one poster telling Nadene that "Families are forever and you are never alone."
Jonah Lomu died on November 18, 2015, and was laid to rest at a funeral on December 1.
The ceremony was an emotional affair for Lomu's family.
Jonah's two sons with Nadene - Brayley and Dhyreille - opened the ceremony by singing a duet, I am a child of God, dedicated to their father.
A choir led the audience into a closing song, before the casket was carried out of the church by a group of friends and family.