A hearing between the National Standards Committee (NSC) and Toner focused squarely on her steps towards drug and alcohol abuse rehabilitation and risks of possible relapses.
There were questions over whether she might be able to sustain her recovery in the face of practising in such a stressful profession.
The tribunal had heard she had been drug-free since mid-2005.
But after cross-examination, the tribunal panel put some questions to Toner, including how long it had been since she had had a relapse.
She responded that she had been at her lowest ebb in January of this year after "engaging in a four-day methamphetamine binge" with a former associate from Springhill Addiction Centre.
"This was a stunning revelation to counsel for the NSC and to the tribunal," a new ruling says.
The revelations resulted in the standards committee pushing for her to be struck off the roll of barristers and solicitors.
They considered she had misled them and the tribunal "in a manner which was unacceptable" for a practitioner.
Her lawyer argued that a pattern of complex addictions had meant a "long road" for his client, but that since this February she had "turned the corner".
After careful and lengthy consideration, the tribunal found itself unable to reach a unanimous view that striking her off was a necessary response.
"In the exercise of weighing up the severity of the practitioner's conduct we note that no clients were harmed by her actions, which were largely self-destructive," it concluded.
"However, she did do considerable harm to the reputation of the profession as a whole."
Taking into account her "lack of candour" in the course of the disciplinary process, the tribunal made a unanimous decision to suspend her for three years.
Toner will be monitored for a further two years if she chooses to re-enter the profession.
"We do, however, urge that there be a full reassessment of the practitioner's rehabilitation and progress prior to her having a practice certificate issued at the end of what will be the maximum period of suspension imposed by this tribunal."
She was also ordered to pay $7566 in legal costs.
Meanwhile, Dargaville lawyer Gregory Clarke has been struck off for "disgraceful or dishonourable conduct" which involved lying to a client about submitting forms for a disputes tribunal case, when he had forgotten to do so.
Mr Clarke admitted he had "stuffed up badly" but having had two previous findings of misconduct against him in 2001 and 2007, the tribunal deemed he was unfit to practice again.
