Transport MMC for Tshwane Metro Municipality and PR councillor Sheila Senkubuge has resigned, the party confirmed to News24 on Saturday morning.
"I can confirm that we have received her resignation letter," provincial leader John Moody said.
According to Moody, a private citizen had also laid charges against Senkubuge, questioning whether she was eligible to hold a council seat due to her initially holding permanent residency before becoming a naturalised citizen.
When asked if her resignation was linked to an alleged leaked sex recording scandal, Moody said: "It is up to her at the end of the day, she needs to face whatever action she needs to face."
Senkubuge has been embroiled in a scandal at the municipality after a recording allegedly revealed a relationship between herself and Tshwane Mayor Stevens Mokgalapa, who took special leave on Thursday.
In her resignation letter, which News24 has a copy of, Senkubuge said that despite her work successes, there were efforts to personally drag her name.
"In light of recent events, and despite the many successes, it has become clear that attempts to vilify me are taking focus away from the purpose of my role in office. This will in turn inevitably affect service delivery to our residents."
Senkubuge added that all she had done was "at the behest of the people".
"Therefore, as much as it is with regret that I tender my resignation with immediate effect, I do so in order to not betray the spirit, the struggle and the sacrifice that our forebears made and the charge they gave us, which is to always put our people first, as articulated in the Batho Pele principles."
She said residents had to continue getting "the best level of commitment and services from us, as their leaders".
"I believe focus should always be on one thing and that is improving the quality of life of our people of Tshwane. I remain forever humbled and honoured to have been given the opportunity to serve."