Advani said in his 60 years of political life he has not known any of his colleagues "so consistently, so viciously maligned by opponents as Narendra Modi".
The Congress while responding to Advani's defence of Modi said it was a "classic case of self-infatuation".
Writing in his blog, the former Deputy Prime Minister said people, who are part of the "demonising campaign" against Modi, have based their attack on one allegation that Modi did not stop the riots in Gujarat after the Godhra carnage in February 2002.
"The most heartening news I have read in a long, long time" is a report that Special Investigation Team clears Modi of willfully allowing post-Godhra riots, Advani said.
"The country is eagerly awaiting the full text of the SIT report to the Supreme Court," he said.
Congress spokesperson Mohan Prakash said BJP tries to take political advantage if a probe by any investigation agency appears going in its favour, but casts doubts on the functioning of the investigation agencies and constitutional bodies when their findings do not favour it.
"This (the Gujarat riots) is one of the cases being investigated by SIT and that report has been given (to the Supreme Court) in a sealed cover. Modi, BJP or even Advani cannot escape responsibility for whatever has happened in Gujarat," Prakash said.
"Killing of innocents in BJP-ruled state took place when Modi was chief minister and Advani was deputy prime minister and home minister of the country. If they are not responsible, then who else is? This is a classic case of self-infatuation," he added.
According to a media report, the SIT has cleared Modi of the charge that he failed to discharge his constitutional duty to intervene swiftly and stop the communal riots.
When the "calumny campaign" against Modi was at its peak, Modi was receiving kudos from within India and abroad for making Gujarat a role mode state for the country "so far as good and honest governance is concerned."
Advani also said the allegation against Modi was that after the brutal attack at Godhra on a train returning from Ayodhya in which 58 kar sewaks were burned to death and riots broke out in some parts of Gujarat, Modi deliberately allowed the rioters to run rampage.
He also recalled that the Supreme Court appointed the SIT headed by former CBI director R K Raghavan to investigate a petition filed by Zakia Jafri, wife of former Congress MP Ahsan Jafri, that Modi failed to stop riots.
"The Raghavan team investigated the allegations for nearly twenty months. In the course of their investigations the SIT interrogated Narendra Modi personally, and early last week submitted its report to the apex court," Advani noted.