Erika Menendez of Queens pushed Sunando Sen, 46, in front of an oncoming subway train on December 27, telling authorities later that her hatred for "Hindus and Muslims" prompted her to push Sen off the subway platform.
Menendez was due to be arraigned in a federal court today but her arraignment has been postponed till February 27.
At a hearing in a Queens court, her defence team said it would contest a ruling that she is mentally fit for trial.
They want their own psychiatrist to examine Menendez, who has already undergone a psychiatric evaluation.
Queens District Attorney Richard Brown had said earlier this month that Menendez was deemed fit to stand trial.
She has been indicted on charges of one count of second-degree murder as a hate crime and two counts of second-degree murder and faces up to 25 years to life in prison if convicted.
She remains held without bail.
Sen, who had owned a printing business in the city, was cremated on New Year's eve in the presence of friends and business partners.