Officials said they had sought reports from Bally and Rajarhat-Gopalpur which have been sent to the Election Commission in Delhi.
In Bally, there were complaints of false voting while in Rajarhat, it was alleged that state minister and TMC candidate Purnendu Bose had helped malpractices.
BJP and CPI-M had lodged complaints on this with the poll panel.
In the meantime, Deputy Election Commissioner Sandeep Saxena held a video conference meeting to review poll preparedness for the fifth phase of polling on April 30.