Merkel, 64, was seen unsteady while standing alongside Finnish Prime Minister Antti Rinee during a military honors ceremony outside the chancellery in Berlin on Wednesday.
The German leader appeared to visibly shake while the two leaders stood and listened to their respective national anthems play.
Merkel told reporters following the episode that she was “fine” and suggested that the psychological impact of the first incident was responsible for the subsequent episodes.
“I said recently that I am in a phase of processing the last military honors with President Zelenskiy. That is clearly not entirely complete, but there is progress," she said.
The first time Merkel was seen shaking was on June 18 as she stood alongside Ukrainian President Volodymyr Zelenskiy at a military honors ceremony.
The second incident on June 27 rekindled concerns over her health after she was seen again unsteady at the German president's palace as she listened to his comments on the swearing-in of a new justice minister.
Public figures' health is generally regarded as a private matter in Germany and the country's privacy laws are very strict on that type of information.
Merkel refused to answer further questions Wednesday, telling reporters who pressed the issue that "my comments on this are done today.”
“I think my statement that I am fine can find acceptance," she continued. "I said that I have to process this event and that I am in this process, and I think that just as it came, it will go away one day."
Merkel added that she is “very firmly convinced” that she is “entirely capable” of serving as chancellor, a position she’s held since 2005.
She announced last year that once her term ends in 2021, she will not seek a fifth term, nor will she pursue any other political job thereafter.
Merkel is set to turn 65 on July 17.
The Associated Press contributed to this report.