Nationals leader Michael McCormack has spoken out against extremist elements within his party after it was revealed dozens of NSW members were being investigated over links to neo-Nazi groups.
Up to 20 members are reportedly facing expulsion, after people involved in the alt-right movement were found to have joined the Young Nationals.
"The Nationals will not tolerate extremism or the politics of hate. People found to engage with such radicalism are not welcome in our party," Mr McCormack tweeted on Monday.
NSW Nationals Senator John Williams said he was "totally surprised" white supremacists had targeted the party.
"Why they would do this is beyond me," Senator Williams told ABC radio.
"Why would you align yourself or have any sort of respect whatsoever for such a person as Hitler?"
The executive of the NSW Nationals will discuss the scandal at a meeting in Sydney on Friday.