Among the thousands of tributes made by members of the public to the victims of the Sydney siege, there was a very personal one.

"I love you mum," read the note, illustrated with a drawing of two women, left at the makeshift memorial in Martin Place.

Relatives of Katrina Dawson gather in Martin Place on Thursday. Credit:Reuters

The simple message is from Sasha, the young daughter of Katrina Dawson, who was killed during the siege at the Lindt Chocolate Cafe.