Angela Merkel and Mette Frederiksen sit as they listen to the national anthems in Berlin on Thursday. Tobias Schwarz / AFP

In a rare change of protocol apparently to prevent a repeat of uncontrollable shaking German Chancellor Angela Merkel on Thursday  remained seated during national anthems at an official ceremony.

With questions swirling about Merkel's health after she suffered three episodes of shaking in public in less than a month, the veteran leader opted to play safe.

After greeting Denmark's new Prime Minister Mette Frederiksen at the portico of the chancellery, a smiling Merkel walked her over to a podium where both leaders took their seats before the anthems played.

Asked by journalists if she had seen a doctor over the shaking incidents and about the results of any medical checks, Merkel declined to give specifics.

"You can assume that firstly, I know the responsibilities of my office and that I therefore act accordingly with regard to my health," Merkel said at the joint news conference with Frederiksen.

"And secondly, you can also assume that as a person, I have a strong personal interest in being in good health and that I take care of my health," she said.

Standing next to her at the press conference, Frederiksen said she found the chancellor "as strong and competent as before I came to Berlin today." - 'Live with it' - The unusual decision to use seats came a day after a similar ceremony when the German chancellor was seen shaking involuntarily for the third time.

On Wednesday, Merkel began trembling as national anthems were being played at the reception of Finnish Prime Minister Antti Rinne.

Just over an hour later, she attended a press conference as planned and told journalists that her health was no cause for concern.

She explained that she was simply still in a phase of "processing" a previous shaking spell, but that "there has been progress".

"I will have to live with it for a while," added Merkel, who turns 65 next week.

"Just like how it has come, one day it will go away too," she said.

The shaking on Wednesday was visible although less severe than during the first episode in June.

On that occasion she appeared unsteady and shook as she stood in the midday sun next to Ukrainian President Volodymyr Zelensky, whom she was welcoming with military honours.

That first bout of shaking was blamed on dehydration. But a second episode struck a week later at the end of June, just hours before she was due to board a plane for a G20 summit in Japan.

Officials have sought to play down the repeated shaking, insisting that Merkel is well while refusing to address detailed questions about her medical condition.

Agence France-Presse