About 800 of Tamil protesters rallied in Sydney's Central Business Distinct on Sunday, stopping traffic and residents in their tracks.
"This time around we're calling on our friends, our family and our neighbors in the Australian community to start boycotting Sri Lankan products," Protest spokeswoman Sam Pari told reporters.
Foreign Minister Stephen Smith on Wednesday has called on the Sri Lankan government to break off hostilities to allow civilians to leave the conflict, but his statement did not go far enough, Pari said.
"We welcome the statement because something is better than nothing, but we still haven't seen any action. Words only go so far," Pari said.
According to the Tamil, 6,500 people have been killed in the past three months in the long-running civil war.
The Sri Lankan government said it is on the verge of defeating the Liberation Tigers of Tamil Eelam, the rebel group which has been fighting for a separate Tamil homeland since 1972.
The remaining Tigers are trapped in the no-fire zone, in the island's northeast, along with thousands of civilians.