Rabri Devi, wife of RJD president Lalu Prasad, had last month during a her party function commented that elderly members of RSS do not feel ashamed of coming out in public wearing half-pants.
"She is a woman having a mindset of 19th century," Modi told reporters reacting to controversial comments of Rabri Devi.
"Not only children, elderly people wear shorts nowdays as part of the latest fashion while going to shopping malls or excursion," Modi, who has his background in the RSS, said.
On this, Modi said RSS is a "flexible organisation" which from time to time change dress code for its members.
"Earlier, RSS cadre like me used to wear leather shoe and belt which are not in use now," he said.