Jessica Payne, a member of Socialist Alternative who is organising the rally, said the Australian government must not join the chorus of world leaders "demanding Assange's head on a plate".
"His crime is simply that he has published the comments and thoughts of some of the most powerful people in the world," she said.
"Even the Prime Minister could not come up with a charge against Assange.This is an attack on freedom of speech and us as citizens, our right to know what our rulers and elected representatives are up to," she added.
Last week Australian PM Julia Gillard condemned the cablegate.
The lawyer who defended Doctor Mahomed Haneef against spurious terrorism charges Peter Russo will be one of the people protesting in support of Julian Assange on Friday.
Assange has been denied bail in London after his arrest on a Swedish warrant for suspected sex crimes charges he denies. (With PTI Inputs)
Election Results for Lok Sabha Election 2019 will be out on May 23. Get the latest election news and live updates on ndtv.com/elections. Catch all the action on NDTV Live. Like us on Facebook or follow us on Twitter and Instagram for news updates from each of the 543 parliamentary seats for the election 2019