SYDNEY, Australia — Senator Sam Dastyari was trying to order a drink in Melbourne on Wednesday night when he was interrupted at the bar by some unfriendly patrons.

A group of three men, identifying themselves as members of Patriot Blue, a far-right group, walked up to him and began hurling racial slurs at the lawmaker, who is a member of the Australian Labor Party.

“You terrorist,” one man is heard saying in a video they uploaded to Facebook. “You little monkey.” Then, following Mr. Dastyari around the pub, they continue to throw insults his way. “Why don’t you go back to Iran, you terrorist?”

The lawmaker initially tried to brush the insults aside but then called them out.

“Honestly, I think you guys are a bunch of racists. I don’t have time for you,” said Mr. Dastyari, who is of Iranian heritage and a nonpracticing Muslim.