Prime Minister Scott Morrison has urged police to apply “the full force of the law” to Queensland Senator Fraser Anning after he was filmed punching a teenage boy who cracked an egg on his head.

By 11.15pm on Sunday more than one million people (1,021,915) had signed a petition calling for Mr Anning to be sacked, while global leaders including New Zealand’s Prime Minister Jacinda Ardern had condemned comments made by the senator in the wake of the Christchurch massacre.

As Parliament moves to formally censure the former One Nation MP over his decision to blame Muslim migration for the mosque murders, a police investigation is under way into an ugly weekend clash in Melbourne.

A 17-year old Victorian teenager cracked an egg on Senator Anning’s head in protest over the comments on Saturday.

Footage of the incident shows Senator Anning striking the boy twice, first with a slap and then a punch before he is wrestled to the ground by the senator’s supporters and held in a chokehold, while journalists urge the men to release the pressure around the boy’s neck.

“I think the full force of the law should be applied to Senator Anning,” Mr Morrison said.

Victorian Police said they are investigating the actions of both the teenager and Senator Anning during the weekend clash.

“During this time it is alleged a 17-year-old Hampton teen assaulted a 69-year-old man from Brisbane by breaking an egg on his head,” a spokesman said.

“The incident is being actively investigated by Victoria Police ‘in its entirety’, including the actions of the 69-year-old man and others.”

On his return to Queensland, Mr Anning was confronted by angry protesters at the entrances of the Brisbane Gun Show, where the Senator was in attendance.

The censure motion against Senator Anning has no practical effect on the controversial MP’s vote in the Senate.

It does not result in any ban or suspension from the Queenslander participating in votes or debates.

However, it will be jointly moved by the Morrison government and the Opposition in a show of bipartisan condemnation “for his inflammatory and divisive comments seeking to attribute blame to victims of a horrific crime and to vilify people on the basis of religion”.

Labor leader Bill Shorten said the teenager who attacked Senator Anning had done a “mug thing” but Senator Anning had questions to answer.

“You, by your hate speech, have created a swampland of hatred through your ideology of hatred,” Mr Shorten said.

“You cannot disown what has crawled out of your swamp.”

Senator Anning is unlikely to be re-elected to the Senate at the May election. With Parliament not set to sit again until July, it’s likely he will not return to Canberra.

Earlier, Mr Morrison also raised concerns about the role of social media during the attack.

“First of all I’d say that the social media companies co-operated with authorities over the last 48 hours, so I’m making no comment against their willingness to co-operate,” Mr Morrison said.

“But I sadly have to say that the capacity to actually assist fully is very limited on the technology side. In the past, they have suspended this sort of Facebook live-streaming and assurances were given that when it was put back up, it could avoid this. Clearly it hasn’t.

“So I think there are some very real discussions that have to be had about how these facilities and capabilities as they exist on social media, can continue to be offered, where there can’t be the assurances given at a technology level, that once these images get out there, it is very difficult to prevent them.

“But we will be seeking to get assurances from the social media companies about their capability to ensure that this tool cannot be used by terrorists.”