Sizakele Sigasa and Salome Masooa were killed because they were lesbians.
This is according to the Positive Women's Network, an organisation advocating for the rights of South African lesbians, which said on Thursday that their murders "appear to have been a hate crime, committed by people who are intolerant of women and lesbians".
Sigasa was an outreach co-ordinator at the network.
The two women were found murdered in Meadowlands, Soweto, on Sunday.
Sigasa sustained three bullet wounds to her head and three to her collarbone. Her killers used her underwear to tie her hands and the shoelaces of her new training shoes to tie her ankles.
Masooa sustained a single gunshot wound to her head.
On Thursday, more than 200 people crammed into a small hall on the premises of the Ipelegeng Community Centre in Soweto to pay tribute to their friends and colleagues.
Various speakers paid heartfelt tribute to the women, particularly Sigasa, who played a prominent role, along with Deputy President Phumzile Mlambo-Ngcuka, during the formulation of the national strategic plan to fight HIV and Aids.
Dawn Cavanagh, director of the Forum for the Empowerment of Women, spoke about how Sigasa had persuaded the deputy president to prioritise issues dealing with lesbian and gay rights.
Cavanagh said Sigasa was always among the women who gathered at the Johannesburg High Court under the banner of "One in Nine" in support of the woman who accused Jacob Zuma of rape.
"She was fearless. She was relentless," the aggrieved Cavanagh said.
During her address, Cavanagh called on the lesbian and gay community not to rest until the killer, or killers, were prosecuted.
"We have to call for justice for rape victims. Only 7 percent of rape perpetrators are prosecuted. We need to say enough is enough," Cavanagh urged.
There was silence in the hall when Susan Pheto, who has been involved with Sigasa for the past 15 months, recommitted her love to her.
Pheto told how Sigasa had helped her to deal with the trauma after she was raped by someone who was supposed to protect her.
Dedicating her pledge to Sigasa, she said: "I will never stop loving you."
Sigasa and Masooa will be laid to rest on Saturday.
Earlier Carrie Shelver, of People Opposing Women Abuse, "generally" condemned the women rights movement for not doing enough to deal with lesbian rights issues.
Shelver went on to say that these movements generally wanted lesbian communities to deal with their problems on their own.