President Donald Trump is set to welcome Malaysia's Prime Minister Najib Abdul Razak to the White House on today, a meeting expected to focus on security issues while steering clear of a US investigation into a Malaysian corruption scandal.

The visit is important for Najib, who faces elections next year and wants to signal he is still welcome at the White House despite a criminal probe by the US Department of Justice (DOJ) into a state fund called 1MDB.

Najib founded the fund, which is facing money laundering probes in at least six countries including the United States, Switzerland and Singapore. He has denied any wrongdoing.

The White House said it would not comment on the DOJ investigation.

"Investing in a long-term relationship between our countries, that in itself provides a foundation for us to address issues of concern, and that would include corruption and transparency," a White House official said, speaking on condition of anonymity.

Trump plans to talk with Najib about North Korea's nuclear provocations, and ways the US and Malaysia could do more to halt the expansion of the Islamic State (IS) in Southeast Asia, White House spokesperson Sarah Sanders told reporters on yesterday.

South China Sea issues

The South China Sea will also be part of the talks, as will trade and investment, Sanders said.

Malaysia has increased military cooperation with the US in the South China Sea, where it has overlapping claims with several countries.

"Malaysia is particularly anxious about the Chinese Navy's activities off the coast of Sabah and Sarawak, where state-owned Petronas is pumping oil and gas," said Murray Hiebert, a Southeast Asia expert at the Centre for Strategic and International Studies in Washington.

Najib had once enjoyed close ties with Trump's predecessor Barack Obama, playing golf with the Democratic president in Hawaii in 2014.

But relations cooled over the 1MDB scandal. The Justice Department sued to seize some US$1.7 billion in assets it said were bought with misappropriated 1MDB funds.

The Obama administration had also become critical of a Malaysian government crackdown on the media and political opponents.

Najib, who has boasted about golfing with Trump, is less likely to hear about human rights issues from the Republican.

"With Trump in the White House and his administration's downplaying of human rights and democracy, Najib's handling of the opposition is not likely to be a focus of the White House meeting," Hiebert said.

- Reuters