TORONTO -- A Toronto judge says he needs more time to consider whether a further mental health assessment is needed for a man found guilty in a terror plot to derail a passenger train.

The issue of Chiheb Esseghaier mental health, which came up during his sentencing hearing, has brought into question whether the Tunisian national is fit to participate in the legal process.

Justice Michael Code has been mulling over whether to order a fresh mental health assessment to determine if Esseghaier is fit to be sentenced after Crown lawyers said they want one.

That followed an assessment from a psychiatrist who testified she believed Esseghaier is unable to participate in his sentencing hearing because he is likely schizophrenic.

The judge was to deliver his decision Friday afternoon but when court reconvened, he said the issue is "much more complicated" than he thought.

Code said he still hadn't decided if a further mental health assessment for Esseghaier was needed, and even if it was, he said there were serious jurisdictional issues around assessing the mental fitness of someone who has already been convicted.

Esseghaier and his co-accused Raed Jaser were found guilty in March of a terror-related conspiracy to commit murder -- which carries a sentence of up to life in prison -- and six other terror-related charges between them.

Esseghaier's mental state has become a key issue after court heard testimony from the psychiatrist who examined him.

Esseghaier, who is self-represented, called Dr. Lisa Ramshaw's diagnosis "lies" and expressed his anger in court at her testimony.

Ramshaw's assessment of Esseghaier was ordered in May at the request of a lawyer appointed to assist Esseghaier through the legal process.

Code has asked Crown lawyers if they would consider reframing their request for a further fitness assessment for Esseghaier under the Mental Health Act, as opposed to the Criminal Code.

"The biggest difficulty I'm having is with jurisdiction," he said. "The whole criminal code regime for fitness at trial has nothing to do with this case."

The ordering of any further fitness assessment for Esseghaier could have implications for Jaser, whose lawyer has said he will ask for his client's sentencing to be adjourned.

During Jaser and Esseghaier's trial, court heard that an undercover FBI agent gained the men's trust and surreptitiously recorded their conversations, which made up the bulk of the evidence in the case.

The two were recorded speaking about alleged terror plots they would conduct in retaliation for Canada's military actions in Muslim countries, including the derailment of a Via Rail train travelling between New York and Toronto.

Esseghaier refused to participate in his trial because he wanted to be judged under the rules of the Qur'an.

Jaser's defence lawyer argued his client was only faking interest in a terror plot as part of an elaborate con to extract money from Esseghaier and the undercover agent.