Queensland senator Fraser Anning struck out twice with an open hand at a teenager who smashed an egg on the back of his head during a media conference at a right-wing rally in Melbourne on Saturday.
As supporters gathered around the reporters to hear Senator Anning interviewed by The Age and television news members, a young man standing behind him smashed an egg on the back of the senator's head.
Senator Anning turned and struck at the 17-year-old in the head with an open left hand, then lashed out again with his left hand towards the teenager's head.
A slew of Senator Anning's supporters gang-tackled the teenager and pinned him to the floor.
The teen was held on the ground for an extended period of time until journalists appealed to the Anning supporters to allow the person to get back on his feet.
Far-right activist Neil Erikson, who was involved in the gang-tackle, shouted at the organisers to remove reporters.
"Get the journalist out of here... If you don't like, get out," he said.
Police are investigating the incident and Senator Anning's retaliation.
The teenager has been released without charge pending further investigions.
Senator Anning earlier delivered an impromptu speech to about 100 supporters at Moorabbin in Melbourne's south-east, in which he doubled down on his comments blaming Muslim immigration for Friday's Christchurch shooting.
When Senator Anning also said many of his supporters in his home state of Brisbane were under 35, one person from the crowd noted that the alleged Christchurch shooter was aged 28.
"It's the younger generation taking up the fight", said the supporter.
Anning responded: "well he's obviously a little on the crazy side, but yeah."