Nalini had moved the High Court against the decision of the Tamil Nadu Government that had rejected her plea for premature release.
It was her second plea to release her early, where she requested the High court to release her under general amnesty.
Nalini, imprisoned in the Vellore Central Jail, has claimed that she was entitled for release since 2005, as she had completed 14 years in jail.
Her original death sentence was commuted to life imprisonment after Sonia Gandhi sought a reprieve for Nalini after she had a baby.
On May 21, 1991, Rajiv Gandhi was killed in a bomb blast at Sriperambudur in Tamil Nadu in a conspiracy hatched by the LTTE.