Posting on Facebook, Kanok said his moral conscience prompted him to quit with the immediate effect.
Kanok stopped short of naming Prinn but his message clearly indicated he was referring to his fellow former Democrat deputy leader.
Kanon signalled his dissatisfaction with Democrat leader Jurin Laksasnawisit’s actions after Prinn was hit with multiple charges of sexual misconduct and rape.
Prinn quit the party earlier this month after being accused of sexual harassment.
Lawyer Sittha Biabungkerd, who is representing Prinn’s accusers, says 14 women have so far filed police complaints against the former Democrat high-flyer.
Jurin last week resigned as chairman of two panels on women’s rights and promised the party would conduct an investigation and remedy Prinn’s accusers. He brushed off calls for his resignation as party leader, insisting he had to stay on to take responsibility for the controversy.
But Kanok said that society was disappointed with the party’s handling of the controversy.
“The party leader’s actions do not match public expectations of the party’s responsibility to society,” Kanok said.
“The Democrats have always worked with determination in service to the people, in line with the definition of their name. But now it seems clear that the public is dismayed with the party’s decision, led by the leader, regarding what happened.”
Kanok did not spell out what actions he wanted Jurin to take.