The Democratic Alliance-run Mogale City became embroiled in more controversy after all parties apart from the ANC boycotted a sitting on Wednesday to elect a new mayor.
It follows the removal of DA mayor Michael Holenstein last week in a secret motion of no confidence, with 38 councillors against the motion and one deferred.
The DA-led coalition at Mogale City has a majority of 39 seats to the 38 of the ANC which means someone turned in last week's vote.
All 27 DA councillors in Mogale City then underwent voluntary lie detector tests to determine who had voted with the ANC to depose Holenstein, DA Gauteng leader John Moodey told News24 on Tuesday.
"Members of that caucus decided on their own that they would go through with the test. Every member was made very aware of the fact that they are not forced by any law to go through such testing," Moodey said.
Council speaker and ANC member Patrick Lipuli questioned how the DA could ask ANC MPs to vote openly for a motion of no confidence against President Jacob Zuma, but did not apply the same system in their own party.
"They are hypocrites. I don't believe they volunteered. They are being forced and subjected to this."
Councillors were set to elect a new mayor on Wednesday but only ANC members turned up, setting social media aflame.
Some pointed out the hypocrisy of the DA calling for a secret ballot against Zuma.
What was the point of the secret ballot if DA councilors have to do a polygraph test #MogaleCity— M O L E B O H E N G® (@Simply_Lebo_) June 14, 2017
#MogaleCity Hearing that one DA Councillor has resigned with immediate effect. remember yesterday they underwent lie detector tests?!— Matshidiso Madia (@tshidi_lee) June 14, 2017