Wickrematunga's Sunday Leader newspaper has been virulently anti-establishment and regularly savaged the government for its war against the Tamil Tigers.
Last Thursday he was shot at close range near the capital Colombo by unidentified gunmen. The attackers escaped even though the murder took place in an area near an airbase where the military has a large security presence.
Sri Lankan opposition parties were united in condemning his execution-style murder late last week, with fingers pointed at the government for his killing as well as a string of recent attacks against the media.
Mr Wickramatunga was a permanent resident of Australia and Radio Australia reports the Australian government says it's disturbed at a trend that's seen 15 media workers killed in Sri Lanka in recent times.
Reporter Linda Mottram says the foreign minister Stephen Smith says Mr Wickramatunga's death was effectively an assassination which he says Australia deeply regrets.
And with Amnesty International reporting 15 media workers now killed in Sri Lanka, Mr Smith says he sees a disturbing trend.
