US President Donald Trump will test his deal-making prowess in a region battered by his hardball trade policies on a trip to Asia next week, as doubts hang over his highly anticipated meeting with China's Xi Jinping.

Trump, who left Washington last night, is set for a five-day trip spanning Malaysia, Japan and South Korea, his first to the region and his longest journey abroad since taking office in January.

The Republican leader hopes to pile up trade, business and ceasefire deals before turning to the toughest challenge, a face-to-face with Xi on Thursday in South Korea.

The trip comes as Trump works to maintain the signature foreign policy achievement of his second term, a fragile ceasefire he helped strike in the Israel-Gaza conflict, while the Russian war in Ukraine rages and a trade war with China shows little sign of abating.