The massacre, dubbed the "2-28 Incident", began on February 28, 1947, after a group of KMT soldiers beat up a women street vendor for selling contraband cigarettes.
 
The incident touched off riots across Taiwan and Chiang, then China's leader, ordered troops from the mainland to put down the crowds, leading to thousands of deaths.
 
The massacre was a taboo subject under Chiang's 26-year dictatorial rule of Taiwan until he died in 1975.
 
It was not until 20 years later that Lee Teng-hui - then Taiwan's president and leader of the KMT party - made the first official apology, prompting parliament to compensate surviving relatives.
 
Chen Shui-bian (centre) has been accused
of politicising the memorial [AFP]
Chen has told relatives of the victims of the massacre that he wants to uncover the truth and bring the culprits to justice.
 
A government-funded report released last year found Chiang had ordered the crackdown, the first time the nationalist leader was officially held accountable for the killings.
 
Chen has repeatedly said that Chiang, who died in 1975, "should face justice and stand trial" for the 1947 killings, dubbed the "February 28 Incident".
 
Speaking on Wednesday at the opening of a memorial hall to the victims of the massacre, Chen said the nationalist KMT had yet to accept responsibility for the killings and the ensuing period of martial law period, during which tens of thousands of Taiwanese were imprisoned without trial.
 
Many were also executed on trumped up charges.
 
"If the nationalists want to reflect on history they should apologize for the martial law period," Chen said.
 
"If the nationalists are unable to reflect on history all the apologies they are making will not earn the trust of the people."
 
Chen's comments on the massacre and his attacks on the opposition have been condemned by critics as political opportunism.
 
They say he is using the anniversary, along with calls to remove Chiang's name from a landmark memorial hall in central Taipei, to boost his popularity for upcoming legislative and presidential elections.