German Chancellor Angela Merkel on Thursday insisted she took care of her health after remaining seated during national anthems at an official ceremony, in a rare change of protocol apparently to prevent a repeat of uncontrollable shaking.

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."