Ban, who last week said Myanmar's transition had reached "a critical moment", is due to meet Aung San Suu Kyi for the first time and speak in the country's fledgling parliament during his three-day trip.
His is the latest in a string of high-level international visits amid a thaw in the army-dominated nation's relations with Western nations, which have begun rolling back sanctions against Myanmar to reward political changes.
The UN Secretary General, who has been to the country twice before, last visited Myanmar when the junta was in power in 2009 but was not allowed to see the Nobel laureate.
Suu Kyi today said that Myanmar was "looking to a better future" and expressed the hope for more "sustainable reforms" during a press conference following talks with German Foreign Minister Guido Westerwelle.
"I do not think that you can say that this process is irreversible," she said, but added that "all those who are in the position of power including the army is formally behind it".
Ban, who has said he would discuss ways the UN could help the country, travelled to Naypyidaw late today and is set to hold talks with President Thein Sein tomorrow. He is then due to give an address to the country's parliament -- the first by a visiting foreign dignitary.