In a decision that opens the door to Mr Nitschke renewing his registration to practice medicine in Australia, the Northern Territory Supreme Court on Monday ruled he had been unfairly treated.

In June last year, the Medical Board of Australia used its emergency powers to suspend Mr Nitschke's registration over revelations he had communicated with a suicidal man Nigel Brayley, who later took his life with a method recommended by Mr Nitshcke's group Exit International.

The board ruled that Mr Nitschke had given tacit approval to suicide when he failed to refer Mr Brayley to another doctor for psychiatric assessment. They said this flouted the doctors' code, which states "doctors have a responsibility to protect and promote the health of individuals and the community".

But on Monday, Justice Graham Hiley said the board's decision to suspend Mr Nitschke's medical licence was based on a misreading of the code of conduct for doctors in Australia. He said "there was no basis" for the decision given that section of the code did not provide any context to how it should be applied.

Mr Nitschke's lawyers successfully argued that because Mr Nitschke was not engaging with Mr Brayley as a patient, the board's finding meant doctors would be obliged to treat strangers they met in a social setting as though they were patients.

Mr Nitschke had earlier appealed unsuccessfully to the Health Professional Review Tribunal to have the board's decision to suspend him overturned.

Mr Brayley, 45, was being investigated over the murder of his wife and the disappearance of a former girlfriend when he attended one of Mr Nitschke's Exit International seminars. In later emails to Dr Nitschke, Mr Brayley told of his plans to take his own life, eventually using a drug mentioned at the seminar.

Mr Nitschke said he felt vindicated by the Supreme Court's decision. "I feel I have been subject to some pretty unfair treatment by the disciplinary bodies of the medical profession and I think that has been shown to be the case," he said.

"Today, the court has tossed out the Medical Board's political persecution of me."

Mr Nitschke said he had no plans to pay his medical registration fees and said he would be considering his position for 12 additional complaints the board is set to bring against him.

For help or information call Suicide Helpline Victoria on 1300 651 251 or Lifeline on 131 114, or visit beyondblue.com.au