A second envelope containing a powder has caused alarm at the Adelaide office of Senator Sarah Hanson-Young.
The delivery prompted an evacuation of the Greens' headquarters for the second time in 24 hours, after a first envelope containing powder and a threat was received on Monday.
The powder in both packages was tested and found not to be a dangerous chemical, a police spokesperson told AAP.
The South Australian senator, who was returned at Saturday's election, has not detailed what was in the note but has confirmed it was directed at her.
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She labelled the person who sent it an "idiot".
"It was white powder with a pretty serious threat attached," she told ABC radio on Tuesday.
"Everyone is fine. The staff are fine but of course, it's not a nice thing for those staff on the front line who receive the mail to have to deal with.
"Whoever did this well, frankly, they're an idiot."
Senator Hanson-Young said the incident was disappointing after the election which was a wonderful celebration of democracy.
"The idea that some people think that threatening politicians, putting staff in danger as they do that, is okay is really disappointing," she said.
"But it's not the view of most people."
