She also rejected reports that the Centre was celebrating the day as 'Guru Utsav', saying it was the name of an essay competition and wondered if those criticising her were doing it deliberately for political reasons.
She stressed that September 5, the birth anniversary of former President the late S Radhakrishnan, will continue to be celebrated as 'Teachers' Day'.
"This particular activity is voluntary in nature. If it is being politicised, then I would say it is regrettable," Irani told reporters when asked about the objections raised in some states over the Centre's directive to them to ensure students' participation in the event.
The scheduled timing of the prime minister's speech, from 3 P.M. To 4.45 P.M. Has also come under attack from parties like Congress.
Reacting sharply, Irani said, "If the prime minister of a free India does not have the freedom to interact with students, then it is ridiculous."
As to the 'Guru Utsav' row, Irani said her ministry had sent a representation to all states about an essay competition under that title in their language. She claimed that over 1.3 lakh students have already taken part in the contest.
Modi is to give a pep-talk to about 1,000 selected students at the Manekshaw Auditorium here on September 5. The programme, which will see Modi interact with the students and take questions via video conferencing facility, will be beamed live to over 18 lakh government and private schools in the country through Doordarshan and education channels.