Federal Greens leader Richard Di Natale says he has referred a "disgraceful" Facebook post by MP George Christensen to federal police.
Mr Christensen posted a photo of himself pointing a hand gun and the comment "you gotta ask yourself, do you feel lucky, greenie punks?".
Saturday's post drew widespread attention and the Queensland Nationals MP was accused of being insensitive in the wake of last week's high school shooting in the United States.
Senator Di Natale reported the image to the Australian Federal Police, saying Mr Christensen was giving licence to people to behave in a violent way towards others with a different view.
"It's disgraceful, irresponsible, it's shameful," he told ABC radio on Monday.
Anti-Adani protestor Ben Pennings confirmed on Sunday he had added Mr Christensen's post to a complaint he filed on Thursday with Queensland police after receiving over 100 death threats online.
"George Christensen is an appalling example to his constituents and should be ashamed of himself," Mr Pennings said.
"When tensions are high, threats of physical violence to peaceful protesters are particularly unacceptable."
Mr Christensen later amended his post to read "You gotta ask yourself, do you have a sense of humour, greenie punks? Obviously not".
Queensland police said on Sunday night no offence had been committed.
Liberal MP Ian Goodenough, a member of the parliamentary friends of shooting group, said it appeared Mr Christensen was making a lighthearted reference to the Clint Eastwood movie 'Dirty Harry'.
"In this case I do not believe that George is making an actual threat against any particular person," he said.
But Mr Goodenough conceded it was an off-colour attempt at humour.
Australian Associated Press