Human rights groups estimate that 40,000 civilians perished in the final months of the government campaign against Tamil Tiger rebels that ended in 2009 and have accused Sri Lanka of suppressing dissent in the aftermath.
A small group of Tamils and refugee activists demonstrated and called on Cricket Australia to boycott the Sri Lankan team, likening the situation to apartheid South Africa.
Sri Lanka are currently playing the third and final match of their three-Test series against Australia, in which they trail 2-0, with a series of one-day internationals and two Twenty20 matches to follow.
"As with the South African apartheid regime, Sri Lanka deserves a boycott of cricket tours and other sporting teams," said refugee activist Nick Riemer.
"Sri Lanka President (Mahinda) Rajapakse uses the country's cricket team to promote his dictatorial regime, being constantly photographed with the players and naming Colombo's new cricket stadium after himself," said Riemer of the Refugee Action Coalition.
"The Rajapakse regime is a ruthless dictatorship that deserves to be isolated by the international community."
The protesters also called for Canberra to stop deporting Tamils and other Sri Lankan asylum-seekers back home to face what they said was jailing and possible torture.
Australia has sent more than 500 Sri Lankan men back to Colombo involuntarily since August, deeming them economic migrants under a new crackdown on refugees arriving by boat.
Cricket Australia said the 50-strong group of demonstrators had been allowed to hand out leaflets to "make their case" and described cricket as a unifying rather than dividing force.
"Historically, cricket has been a game that brings nations together rather than stands them apart," a CA spokesman said.
"The majority of Sri Lankans we speak to want to come to the cricket and see their team do well."