Angela Merkel was shaking at a public event for the second time in less than two weeks, rekindling concerns over her health.
The brief incident happened as the German chancellor stood alongside President Frank-Walter Steinmeier at a ceremony in Berlin.
The two were attending a farewell ceremony for Justice Minister Katarina Barley, who is taking up a post in the European Parliament.
Mrs Merkel, 64, was handed a glass of water but rejected it; she appeared fine when she arrived in parliament half an hour later.
A spokesman for the German leader dismissed any concerns over her health.
Addressing questions on whether she would take part in the swearing-in of the new minister and this weekend’s G20 meeting in Japan, he said: “Everything is taking place as planned.”
He added: “The chancellor is fine.”
Mr Merkel first sparked worries after she was spotted shaking vigorously during a meeting with Ukrainian President Volodymyr Zelensky on 18 June.
She dismissed the concerns at the time, saying she was just dehydrated, and felt better after drinking some water.
Germany is currently experiencing a record-breaking heatwave that has engulfed much of Europe.
On Wednesday, a station in Coschen, Brandenburg, recorded a temperature of 38.6C (93F), toppling the country’s June record of 38.5C from 1947.