German Chancellor Angela Merkel dismissed concerns about her health after visibly trembling at an official ceremony, saying she was just a bit dehydrated in the heat.

Merkel appeared unsteady and was shaking as she stood in the midday sun in Berlin on Tuesday next to visiting Ukraine's new president Volodymyr Zelensky, whom she was welcoming to her office building with military honours.

Mrs Merkel's whole body visibly shook and she pursed her lips as she tried to contain the situation as she stood with Zelenskiy in the 28C (82F) heat while a military band played their national anthems outside the chancellery.

But following the anthems, Mrs Merkel seemed better, walking quickly along the red carpet with Zelenskiy into the building, pausing to greet the military band and taking a salute.

German Chancellor Angela Merkel visibly shook for around a minute while standing next to Ukraine's new president Volodymyr Zelensky

Concerns were raised for the German Chancelllor's health after her 'trembling spell' greeting Ukraine's President Zelensky in Berlin today

Asked by reporter about her wellbeing at a news conference about 90 minutes later, Merkel smiled: 'Since then I've drunk at least three glasses of water, which I apparently needed, and now I'm doing very well.'

Mrs Merkel, who turns 65 next month, smiled broadly after a reporter asked whether her shaking was a cause for concern, saying that she was fine.

Zelensky made light of Merkel's uneasy spell, joking that he would have come to her rescue if necessary.

The 41-year-old said: 'She was standing next to me and completely safe.'

German Chancellor Angela Merkel welcomes Ukrainian President Volodymyr Zelensky upon Zelensky's arrival at the Chancellery today

Angela Merkel seemed to have recovered by the time the two leaders arrived inside to speak to the media

About an hour later following their meeting, Mrs Merkel told reporters at a joint news conference that they had discussed bilateral issues and the Minsk peace process during Zelenskiy's first visit to the German capital as president.

The dpa German news agency reported that this was not the first time Mrs Merkel has been seen shaking under similar circumstances in the hot sun.

It did not give a date for that incident, but said it was also ascribed to Mrs Merkel not drinking enough water.

Mrs Merkel told the media she just needed some water after she visibly shook while listening to a marching band play the national anthems of Germany and Ukraine

Merkel seemed to recover after the anthems as she and Zelenskiy walked into her office building in Berlin today

And in 2014, Mrs Merkel postponed a television interview at the last minute after reported weakness, but her spokesman said at the time she was able to carry it out later after eating and drinking something.

It is not publicly known if Mrs Merkel, who has led Germany since 2005, has any health problems.

German privacy laws are very strict on that type of information being published by the media.

Merkel is frequently called the European Union's most influential leader and the most powerful woman in the world.

She has said she will leave politics at the end of her current term, in 2021.