The comments come after an escalated conservative campaign against the liberal press which has seen the closure of virtually all its newspapers and magazines.
"Today enemies are trying to undermine the sovereignty of Islam by using some sections of the press", Mr Rafsanjani said in a Friday sermon at Tehran University.
He said efforts "to strip the Islamic revolution of its Islamic content" were now even more expert and resourceful than after the revolution itself in 1979.
But he issued a thinly-veiled threat of violence against "mercenary writers" who adopted the position of the enemies of the Islamic Revolution.
"The enemies should know that they would take the dream of regaining their dominance over Iran to their graves," he said.
The sermon was covered by state radio and TV.
Confrontation
Pro-reformists seem to have heeded the moderate President Muhammad Khatami's calls for calm in the face of what they regard as growing provocations from Iran's powerful conservative faction.
Mr Rafsanjani strongly criticised allies of Mr Khatami who attended a controversial conference in Berlin earlier this month.
He accused them of shameful conduct in attending the meeting, which was disrupted by an exiled opposition group, and during which a woman was filmed dancing with bare arms.
Mr Rafsanjani alleged that the conference was aimed at denouncing every aspect of Islam and that it seemed to have been planned by the United States.
BBC regional analyst Pam O'Toole says the former president's choice of words suggest the conservative clergy is not in the mood for compromise.
He warned that Iran's Revolutionary Guards and their militia forces were strong and that supporters of the Islamic Revolution were present in universities.
Mr Rafsanjani - who was viewed as a pragmatist when he first became president in 1989 - is now regarded as a stalwart of the conservative camp.
He suffered major political embarrassment during recent parliamentary elections where he trailed far behind all the pro-reform candidates.
Recriminations
Correspondents say the current bans are aimed at the heart of President Khatami's efforts to liberalise Iranian society.
The closures have left almost no reformist daily newspapers on the streets.
The moves have prompted an open exchange of recriminations between different authorities.
The Ministry of Islamic Guidance, which has responsibility for the press, had earlier issued a statement publicly criticising the closures and impugning their legality.
The judiciary hit back by taking the ministry to task for supporting what it called publications that had been blatantly breaching Islamic principles.