"The party wants to clarify that Siddiqui had left SP long back and joined BSP on whose ticket he contested Lok Sabha election from Bijnor," party's national general secretary and spokesman Ram Gopal Yadav said in a statement issued here.
He said that later Siddiqui joined the Rashtriya Lok Dal.
"Siddiqui is not a SP member and has nothing to do with the party," Yadav said, asking the media not to project him as SP leader.
Yadav said terming Siddiqui as a SP leader was "outrightly wrong".
Siddiqui, who is the editor of Urdu weekly Nai Duniya, had recently interview Modi in which the Gujarat Chief Minister had refused to apologise for the post-Godhra riots and instead said he would prefer to be hanged if found guilty.
In an image makeover exercise, Modi had said in the interview, "If my government had done this (post-Godhra riots), I should be hanged in public in such a way that it remains a lesson for the next 100 years so that nobody dares to do it (such a crime)".
Siddqiqui was a SP MP before he joined the RLD only to rejoin the Samajwadi Party in January this year.