Santhan, Murugan and Perarivalan are currently lodged in the Central Prison, Vellore, in Tamil Nadu and they are in incarceration since 1991.
Nalini, Robert Pious, Jayakumar and Ravichandran, are undergoing life sentence for their role in the assassination of Gandhi on May 21, 1991 in Sriperumbudur.
The Tamil Nadu government has set a three-day deadline for itself and also to the Centre over the release of the seven convicts.
The Supreme Court had commuted the death sentence of Murugan, Santhan (both Sri Lankan Tamils) and A G Perarivalan on the ground of 11 years delay in deciding their mercy pleas by the Centre.
It had also rejected the Centre's submission that there was no unreasonable delay in deciding their mercy plea and the condemned prisoners did not go through agonising experience as they were enjoying life behind the bars.
Gandhi's assassins were convicted by a TADA court in January 1998 and were awarded death sentence, which was confirmed by the apex court May 11, 1999.