The Gorakhpur MP said there is a limit to freedom of expression and using it for indulging in anti-national activities was "unpardonable".
"The action taken in JNU case is justified and in national interest. Anti-national slogan shouting in JNU shows that some anti-national elements are active there," Adityanath told reporters.
He said there is a "limit to free of speech and expression and taking its benefit if anti-national activities are done, it is unpardonable".
JNU students' union president Kanhaiya Kumar was arrested last week in connection with a case of sedition and criminal conspiracy registered over holding of the event at the varsity during which anti-India slogans were alleged to have been raised.
The BJP leader demanded strict action against those involved in anti-national activities.
"There is a need for initiating strict action against those involved in activities that are not in national interest. The government should strictly deal with such anti-national activities going on in JNU", he added.
The MP had last week termed the anti-national protests at the JNU as signs of "educational lawlessness prevailing on the campus".