Dubbed the "Trump whisperer" for his ability to manage the mercurial US leader, the former Dutch prime minister will face a tough job of convincing Trump that NATO allies are paying enough for their own defense.

Trump has repeatedly called into question whether the United States would defend allies who do not boost their defense spending, causing major jitters as Europe faces an increasingly aggressive Russia on its doorstep.

Rutte will also be trying to smooth over recent tensions between Trump and Ukraine, as a top US negotiator arrived in Moscow to deliver a ceasefire proposal following a swift pivot by Trump towards Russia.

"I expect key messages will be around how much Europe is stepping up on spending, how we all need to do more on defense production, and welcoming progress in pursuit of peace for Ukraine," Rutte's spokeswoman said.

Trump will host Rutte in the Oval Office before the pair have lunch at the White House. The NATO chief will also meet senior Trump administration officials and members of the US Congress.

The visit is Rutte's first meeting with Trump since the US president began his second term on January 20, and comes at a critical time.

Trump is famously skeptical about whether the United States -- by far the biggest military in the transatlantic alliance and ultimate guarantor of Europe's security since World War II -- should continue in that role.

- Defense spending -

The US president's sudden decision to start talks with Russian counterpart Vladimir Putin in February on the Ukraine war further stunned and worried US allies about his commitment.

He has continued to sow doubts in recent days, saying of allies a week ago that "if they don't pay, I'm not going to defend them."

Trump has previously called for allies to lift annual defense spending to five percent of GDP from the current two-percent target, which NATO expected only 23 of 32 members to meet last year.

He has also questioned whether allies would defend the United States -- despite the fact that the only time NATO has invoked its Article 5 collective defense measure was after the 9/11 attacks on the United States in 2001.

NATO allies will be looking to Rutte, a veteran of European diplomacy, to convince Trump that the alliance is worth sticking by.

Rutte is widely credited with rescuing a 2018 NATO summit by talking Trump around on defense spending during his first term.

He also showed typical Dutch directness by brazenly contradicting the president in a previous visit to the Oval Office that same year.

In an exchange that later went viral, Trump claimed it would be "positive" whether or not the EU and the United States managed to clinch a trade deal.

The visiting Rutte scoffed out loud and interjected: "No! It's not positive. We have to work something out."