Samajwadi spokesman Rajendra Chowdhary in a letter to the chief electoral officer accused Adityanath, the Lok Sabha member from Gorakhpur, of making hate speeches and said they were endangering communal harmony in the state.
"Adityanath has been known for his communal statements and we fear that his being made the BJP's star campaigner will amount to vitiating the atmosphere in the run-up to the polls," said Chowdhary, who is also a minister in the Akhilesh Yadav government.
Stating that both the Bharatiya Janata Party leaders had coined a new term "love jihad", the Samajwadi leader requested the poll panel to ban them from campaigning.
The term "love jihad" was coined by Hindu groups for alleged efforts by Muslims who reportedly target non-Muslim girls for conversion to Islam by feigning love.
Eleven assembly seats and the Mainpuri Lok Sabha seat will go to the byepolls Sep 13.
While all the 11 assembly seats were held by the BJP, the Mainpuri Lok Sabha seat was won by Samajwadi chief Mulayam Singh Yadav.
Mulayam Singh vacated the Mainpuri seat over Azamgarh from where too he won.
Election Commission officials said they were ascertaining the allegations made in the letter and would act accordingly to ensure free and fair polls.