Janata Party President Subramanian Swamy had filed a petition on Wednesday that no leniency be shown towards the accused, who claims to be a juvenile, because of the brutal nature of the crime.
A spokesperson of Swamy told reporters that they will appeal in the High Court against JJ Board's verdict.
In his petition, Swamy had said there were discrepancies between the Juvenile Justice Act and the Indian Penal Code.
"The Juvenile Justice Act terms those above 18 as adults while the Indian Penal Code puts it as 12," the petition said. "The concept of criminal responsibility needs to be added into the Act and should allow the court to differentiate between innocent children and juvenile delinquents."
Hearing in the Delhi gangrape case begins in a fast-track court today.
The accused who claims to be a juvenile has produced his school certificate as proof that he is a minor. The school principal's statement has been recorded. The Juvenile Justice Board is expected to decide on his age on Jan 28.