The March 15 mosque shooting accused has put himself on an extreme minimal eating regime in jail and is also not washing.
The Star has learned there is concern about his well-being - but prison authorities cannot force him to eat more.
The Department of Corrections and his Auckland-based lawyer Shane Tait would not answer questions from Star News yesterday, citing privacy issues and the fact the accused is before the courts for the March 15 terror attacks.
A Corrections Department spokesperson said: "As you will appreciate, this prisoner is currently before the court, and to avoid jeopardising these proceedings or prejudicing their outcome, we are limited in our ability to provide further specific information.
"This prisoner continues to be managed in accordance with the provisions set out in the Corrections Act 2004 and our international obligations for the treatment of prisoners."