The Voluntary Euthanasia Society's Wellington chair has been charged with importing a Class C controlled drug.
Lower Hutt teacher Susan Austen, 65, is facing two charges of importing pentobarbitone.
The first importation is said to have occured sometime after March this year and the second on 30 September.
Ms Austen entered no plea to the charges and the case will be back in court in February.
Yesterday police defended their use of a breath-testing checkpoint in Lower Hutt to target euthanasia supporters.
They said the checkpoint was set up earlier this month specifically to identify people leaving an Exit International pro-euthanasia meeting.
The police have since referred themselves to their own watchdog, the Independent Police Conduct Authority.
The authority has received three other complaints - including from someone who was stopped by officers at the checkpoint.
Acting Wellington District Commander Inspector Paul Basham told reporters yesterday that police were investigating a number of suspected assisted suicides.
They were looking into a death in June in which a particular Class C controlled drug was a contributing factor, he said.
There was no indication at the time that the death was suspicious, and the deceased was not suffering a terminal illness.
The coroner referred the death to police, who started an investigation, Mr Basham said.
That investigation was still in its early stages but had revealed other deaths that required further investigation, he said.
Police became aware of the Lower Hutt meeting as a result of their inquiries, and were worried about the welfare of those attending the meeting.