Germany's Merkel warns Trump

German Chancellor Angela Merkel warned Saturday against protectionist tendencies of US President-elect Donald Trump, citing lessons learned in the 2008 global financial crash and stressing the need to "move forward together".

"My profound conviction is that there are more advantages... to moving forward together than when everyone resolves their problems for themselves. I am truly convinced of this," she told a press conference at a meeting of her CDU party.

Asked if she believed "protectionist tendencies" by Trump could pose a threat, Merkel recalled the example of the 2008 global financial crisis, which "came from the United States".

"As heads of state and government (of the G20), we said: 'We must resolve the problem facing us together,'" she said.

"And the response to overcome that financial crisis was not a response based on closing oneself off, but a response which called for cooperation, for common rules, for regulation of financial markets.

"I think this way worked, and naturally we are going to seek dialogue with the new American president," who will be inaugurated on January 20.

On the campaign trail Trump notably threatened to take protectionist measures against Chinese and Mexican imports, and claimed a first success with a decision by US motor giant Ford not to build a new plant in Mexico.

Trump's attitude has fuelled concern in Germany: on Thursday Foreign Minister Frank-Walter Steinmeier said he was "perplexed" by Trump comparing the leak of a dossier of unsubstantiated allegations against him to something that could have happened in Nazi Germany.

During the US campaign, Steinmeier was even more damning, saying the prospect of a Trump presidency was "frightening" for the world.

He compared Trump to a "hate preacher", saying he had much in common with "fearmongers" in Germany's right-wing populist AfD party and advocates of Britain's exit from the EU.