In some of her most pointed criticisms yet of her opponents, the veteran democracy campaigner said some politicians and parties were "stooping low" during their campaigning - although she stopped short of naming names.
"As we have gone around the country campaigning for the 2015 election, we heard that some people or some political parties are breaking the rules or using dishonest ways in their campaign," she told thousands of flag-waving supporters in the eastern town of Tachileik, close to Myanmar's borders with Thailand and Laos.
Myanmar was run for decades by a brutal and isolationist junta but the military ceded power to a quasi-civilian government in 2011 paving the way to this year's elections.
In recent weeks the country has been gripped by a colourful and boisterous election campaign and Suu Kyi's National League for Democracy (NLD) is expected to make major gains.
Also Read
The other major party contesting the vote is the army backed Union Solidarity and Development Party (USDP) loyal to former general turned current Prime Minister Thein Sein.
The road to the polls has been potholed with challenges. The impoverished country stretches from towering peaks in the north to southern tropical beaches, connected by poor infrastructure, and blighted by myriad ethnic conflicts and recent devastating floods.
NLD and USDP officials have previously accused each other of dirty tricks campaigning but neither have provided any smoking gun evidence.
But the NLD has little trust in the country's military.
Suu Kyi's party won a landslide 1990 general election, only for the junta to ignore the result and tighten its hold on power, imprisoning her for years.