According to home ministry sources, the decision was taken after a thorough observation of all activities of the organisation.
The Centre has received reports about SIMI's movements in Uttar Pradesh, Madhya Pradesh, Rajasthan and Delhi, sources said.
The ban on SIMI was going to expire on February 7. The government is extending the ban on SIMI for the fifth time.
The SIMI, an Islamist fundamentalist organisation, which advocates the 'liberation of India' by converting it to an Islamic land, was proscribed under the Unlawful Activities (Prevention) Act in 2002.
In August 2008, a special tribunal lifted the ban on SIMI. The ban was subsequently reinstated by the Supreme Court on August 6, 2008.
SIMI has been charged of carrying out several terror attacks across India, including the 2006 Mumbai serial train bomb blasts, which claimed 187 lives.
It has also been charged of being involved with the Ahmedabad, Jaipur and Delhi serial blasts in 2008.
SIMI members had reportedly undergone training with Hijbul Mujahiddin cadres and they are also involved in a continuous recruitment drive for the Harkat-ul-Jihad-al-Islami.
SIMI was even labeled as a terrorist organisation by the United States.
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Spotted: Abhishek Bachchan in Delhi