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 The Star yesterday, citing privacy issues and the fact the accused is before the courts for the March 15 terror attacks.
A Department of Corrections 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."
The 28-year-old Australian, who has pleaded not guilty to 51 charges of murder and 40 charges of attempted murder, as well as a charge of engaging in a terrorist act, is being held on remand in a high-security wing of Auckland Prison at Paremoremo.
In a surprise move last week, Mr Tait withdrew an application to move the trial out of Christchurch.
He had earlier applied to have the trial, set down for June next year, taken out of the city.
Moving the trial out of Christchurch would have been a major logistical challenge for the courts system, with the many witnesses expected to be called to give evidence.
The cost of moving the trial had been budgeted in the millions.
