German Chancellor Angela Merkel has met US President Donald Trump on the sidelines of the G20 summit in Osaka, amid renewed concerns about her health.

The 64-year-old Chancellor was seen suffering a severe bout of shaking at a function in Berlin on Thursday, just hours before her departure for Japan.

The shaking – nine days after Ms Merkel was seen to have similar problems – occurred at a ceremony at the official residence of President Frank-Walter Steinmeier during the appointment of Justice Minister Christine Lambrecht.

Ms Merkel shuddered for around two minutes, folding her arms to steady herself. Once she began moving again, her condition improved visibly. She refused the offer of a glass of water.

The earlier shaking fit occurred on June 18, as Ms Merkel stood alongside the new Ukrainian President Volodymyr Zelensky during his visit to Germany.

#Merkel filmed shaking for second time this month during official ceremony

DETAILS: https://t.co/VmyydOuuta pic.twitter.com/C6nKAlGmon

— RT (@RT_com) June 27, 2019

The Chancellor said later that she had failed to drink enough during the hot weather at the time.

In Berlin on Thursday, the weather was relatively cool following a period of intense temperatures as western Europe endures a heatwave.

Later on Thursday, Ms Merkel left Germany for the G20 summit in Osaka, as planned. She was photographed with Mr Trump in Japan on Friday morning (local time).

Trump and Morrison catch up for dinner

Meanwhile, Mr Trump offered his congratulations on Mr Morrison’s ‘miracle’ election victory on Thursday night as the pair dined at Osaka’s Imperial Hotel on the eve of the G20 summit in Japan.

He declared it a “tremendous” and “fantastic victory” that “didn’t surprise me” but “surprised a lot of other people”.

“They called it an upset, but I don’t call it an upset. You probably didn’t. Your wife didn’t call it an upset,” he told Mr Morrison.

https://twitter.com/IbrahimBabakr/status/1144263764067389442

Talk also turned to golf, an avid pass-time of the president’s, playing more than 199 games alone last year and often using one of his own 17 golf courses as a backdrop for press calls and diplomacy.

An Australian reporter asked Mr Trump whether he would attend the Presidents Cup tournament in Melbourne in December.

“It might not be easy, but I’d like to,” the president replied.

“That’s a big deal. That’s going to be great. That’s going to be great.”

That parlayed into a formal invitation from Mr Morrison for the president to make his first visit down under.

“I’m sure that he could do a patch on the commentary there as well, his encyclopaedic knowledge of the game is very strong,” Mr Morrison told Sky News on Friday.

The event, the Presidents Cup – a series of games between a US team and another team representing the rest of the world – is to be held at the Royal Melbourne Golf Club from December 10 to 15.

Chancellor Merkel, who has held office since 2005, will be back in Brussels by Sunday night for a summit following the European Union elections.

Doctors have been reluctant to speculate on Merkel’s health.

In the past, she has been commended for her physical resilience and stamina while working a job that involves long hours and frequent long-haul trips.

A government spokesman refused to comment on any medical treatment that she might be receiving.

However, he did say that a Foreign Office doctor accompanies Merkel’s delegation “during larger foreign trips”.

High-ranking German politicians do not have their own personal doctors. In principle, Ms Merkel would be treated by the same doctors who treat the public.

-with AAP