The democracy icon, garlanded by the international community as a moral force during Myanmar's junta years, has remained near-silent despite mounting evidence of army abuses in Rakhine State.
The United Nations has said recent security operations amount to "ethnic cleansing" of the Muslim Rohingya minority, with thousands fleeing to neighbouring Bangladesh.
Suu Kyi, Myanmar's de facto leader, has seen her halo start to slip since her party took power this year after winning the country's first free elections in a generation.
"One version to explain her silence is callous indifference, another is calculated limited messaging... But the most likely is she simply has no control over the Burmese army."
More From This Section
Thousands of Rohingya have fled the army lockdown in Rakhine to Bangladesh, bringing with them horrifying stories of gang rape, torture and murder at the hands of Myanmar's military.
Rights groups say the military has used attacks on police border posts last month as an excuse for a crackdown on the Rohingya, a Muslim group reviled by many Myanmar Buddhists.
It has barred investigators and foreign journalists from the locked-down area and lashed out at reports of abuse as "fabrications".
Suu Kyi, who has travelled to India and Japan during the six-week crisis, has commented only to say a probe into the attacks was underway in accordance with the law.
But she has faced growing criticism for her inaction.
The UN special rapporteur on Myanmar, Yanghee Lee, has slammed the lockdown as "unacceptable".
Researchers at Queen Mary University London said her silence amounts to "legitimising genocide" and entrenching "the persecution of the Rohingya minority".
Even though she led her party to power Suu Kyi is hampered by a junta-era constitution that gives the army a quarter of parliamentary seats and control over security.