DONALD Trump is likely to be good for the American economy in the short term, according to the head of the International Monetary Fund.

Christine Lagarde said the US president's plans for additional investment in US infrastructure and his likely tax reforms will boost America's economic fortunes.

However, she acknowledged that his policies will squeeze international markets.

"That's a tightening that is going to be difficult on the global economy and for which economies have to prepare," Ms Lagarde said during an event at the World Government Summit in Dubai.

Asked how the world missed Mr Trump's rise and the UK's vote to leave the EU, Ms Lagarde described a creeping, "insidious" push toward anti-globalisation and protectionist thought.

"We have been saying globalisation is great, international trade is great - and it is," she said. "But we have not looked at those who were badly, negatively impacted."

She blamed those negative impacts in part on the rise of robots taking jobs, as well as the shrinking gains of the global middle class.

Ms Lagarde cautiously sidestepped questions on her thoughts about Mr Trump being in the White House by saying "this is really a work in progress, there's been of announcements, a lot of tweets, a lot of things being said".

Still, she stressed the importance of data and facts in making decisions.

"I know it's not fashionable at the moment, but I think that facts, figures (and) actual assessment of the reality matter and that we have to be honest about it," she said.

Meanwhile, Hollywood star Meryl Streep has reignited the war of words with Mr Trump, revealing she has become a "target" after first taking a swipe at him in her Golden Globes speech in January.

Addressing a cheering audience at a fundraising gala for the Human Rights Campaign, a national LGBT group, Ms Streep referred to Trump's tweet after her Globes speech, in which he called the celebrated actress "overrated".

"Yes, I am the most overrated, over-decorated and currently, I am the most over-berated actress ... of my generation," she said to laughs.

She noted that she wished she could simply stay home "and load the dishwasher" rather than take a podium to speak out - but that "the weight of all these honours" she's received in her career compelled her to speak out.

"It's terrifying to put the target on your forehead," she said. "And it sets you up for all sorts of attacks and armies of brownshirts and bots and worse, and the only way you can do it is if you feel you have to. You have to! You don't have an option. You have to."

Streep did not elaborate on the type of attacks she may have been subjected to since her Globes speech, or from whom.

The 67-year-old, who received a record 20th Oscar nomination in January, was receiving the group's National Ally for Equality Award.

Introduced by filmmaker Ken Burns, Ms Streep spoke about how early cultures had always put men at the top, but at some point in the 20th century, women, people of colour and other minorities began achieving their deserved rights.

Progress was fast, and so now, "we shouldn't be surprised that fundamentalists, of all stripes, everywhere, are exercised and fuming".

Turning to Mr Trump, she said: "But if we live through this precarious moment - if his catastrophic instinct to retaliate doesn't lead us to nuclear winter - we will have much to thank this president for. Because he will have woken us up to how fragile freedom really is."

The country has now learned "how the authority of the executive, in the hands of a self-dealer, can be wielded against the people, and the Constitution and the Bill of Rights.

"The whip of the executive can, through a Twitter feed, lash and intimidate, punish and humiliate, delegitimise the press and all of the imagined enemies with spasmodic regularity and easily provoked predictability."

At the end, Ms Streep made a passionate call for religious liberty, the right, as she said," to live our lives with God or without Her.

"All of us have the human right to life, liberty and the pursuit of happiness.

Closing she said: "If you think people were mad when they thought the government was coming after their guns, wait until you see when they try to take away our happiness."