An Australian senator who blamed the New Zealand terror attack on Muslim immigration has punched a 17-year-old boy after he was egged at an event in Melbourne.

Video footage recorded at the event appears to show Fraser Anning, a far-right independent Queensland senator, halfway through a press conference when the teenager cracked an egg over his head while filming with a mobile phone. The senator responded by punching the 17-year-old. The teenager was then tackled to the ground by Anning’s supporters and held in a chokehold.

The boy was later taken away by police and released without charge. Victoria police are investigating the incident.

Anning was criticised on Friday after trying to seek attention by saying the mosque attack highlighted a “growing fear over an increasing Muslim presence” in Australian and New Zealand communities.

The Australian prime minister, Scott Morrison, said Anning’s comments blaming the Islamic community for the shooting were “appalling and ugly and they have no place in Australia”.

The prime minister announced the government would censure him.

The Australian Labor party leader, Bill Shorten, said Anning was “chasing a headline”.

“I do wonder if he’s made Australians less safe overseas,” he said. “That’s another reason not to give this fool any more oxygen.”

A change.org petition calling for Anning’s expulsion from parliament has amassed about 250,000 signatures.