He said this on the sidelines of the Verkhovna Rada, Censor.NET's correspondent reports.
According to Chumak, he and his fellow faction members brought up an issue of corruption within the faction.
Chumak said there was no unified faction stance on some critical problems, including information attacks against MPs Serhii Leshchenko and Oksana Yurynets, as well as Kasko and Trepak situation.
"We just want to know the faction's position - whether it is covering for corrupt officials or is purging of them. We have to decide - are we helping the president to clear the country of the corruption or are we messing with him," Chumak said, noting that 'honest people' do not have to leave the faction.
He said that some PPB colleagues proposed that he and his associates left the faction if they do not agree with its positions.
"We do not need to quit - those who discredit it should quit," Chumak noted.
The MP specified that he meant Ihor Kononeko and Serhii Berezenko.
"This is about dirty elections, about lobbying in economy. We are just saying that businessmen should leave and conduct business outside of the parliament," Chumak said.
He noted that a dirty PR-campaign against him is currently conducted by the persons he mentioned due to his participation in the contest to the National agency on corruption prevention.
The conflict will lead to the faction's cleanup, Chumak believes. He also said that "tomorrow will show much more."