Malaysian opposition leader Anwar Ibrahim applied for a judicial review of his conviction for sodomy, his last legal recourse after an appeal was rejected in February.
He has denied the charge that led to his second conviction for sodomy as a fabrication aimed at ending his political career.
Anwar, the ruling party's rising star in the mid-1990s before he fell out with then Prime Minister Mahathir Mohamad, was jailed for five years.
"We filed the application for a review on Anwar's court judgment to set aside the conviction and release him," Anwar's lawyer, N. Surendran, told Reuters.
"It's his instructions and we are acting on his behalf. We believe there has been injustice done and we've got good grounds. The rest is not in our hands."
Earlier this month, a petition by Anwar's family seeking a royal pardon was rejected.
They also applied to the Prisons Commissioner to allow Anwar to attend the ongoing Parliament sitting, which was subsequently rejected.