In an opinion piece published in the Financial Times ahead of an initial International Court of Justice ruling on the issue, she said Myanmar was the victim of "unsubstantiated narratives" by human rights groups and U.N investigators.
She also said the country could itself punish perpetrators through domestic mechanisms.
The ICJ is ruling on Thursday on a request by Gambia for emergency measures in Myanmar to halt violence immediately against Rohingya, to protect the ethnic minority and to preserve evidence of past abuses.