Australia's prime minister has suggested an anti-Muslim senator should be charged after he hit a teen who cracked a raw egg over the legislator's head.

Senator Fraser Anning has been widely condemned for blaming Muslim immigration for terror attacks on two New Zealand mosque that claimed at least 50 lives.

The 17-year-old boy who egged Anning has become an online hero.

Prime Minister Scott Morrison on Sunday took the side of the egger, telling reporters: "The full force of the law should be applied to Sen Anning."

Police allege the boy assaulted the senator with the egg. The boy's name has not been made public.

Police also said Anning "retaliated and struck the teen twice".