Melania Trump concluded her trip to Africa on Saturday by voicing support for her husband's embattled Supreme Court nominee and urging people to pay less attention to what she wears.

The U.S. first lady said the message of her tour to Ghana, Malawi, Kenya and Egypt was to show the world that "we care."

She dismissed reports about alleged derogatory comments reportedly made by President Donald Trump about African countries and said the issue had not come up on her visit.

The stylish former model also said she did not always agree with her husband’s tweets and gave him her opinion directly, even though he does not always follow her advice.

The four-country trip was a coming out of sorts for the first lady in the world stage. It was her first major solo trip abroad and a rare example of a time when she has answered questions by reporters.

Speaking in Cairo on the tour's final leg, Trump praised Supreme Court nominee Brett Kavanaugh and said she was glad he and his accuser had a chance to be heard following allegations of sexual assault.

"I’m glad that Dr Ford was heard. I’m glad that Judge Kavanaugh was heard, FBI investigation was done - is completed - and (the) Senate voted," Trump said, referring to psychology professor Christine Blasey Ford who had accused him of sexually assaulting her.

Kavanaugh has denied all the allegations.

Trump declined to say whether she believed Ford.

"We need to help all the victims, no matter what kind of abuse they had," she said. "I’m against any kind of abuse."

Kavanaugh looked likely to win final Senate confirmation on Saturday, weathering the sexual assault allegations and attacks on his character and temperament. His confirmation would give the U.S. president a clear win in his drive to cement conservative dominance of the high court.

Trump flew to Cairo from Nairobi earlier on Saturday on the last stage of her visit to Africa, a continent her husband once referred to derisively.

President Trump has been quoted as saying immigrants from Africa came from "shithole countries". He denied making the remark.

Trump said that her husband's alleged derogatory comment about African countries did not come up on her trip.

"Nobody discussed that with me, and I never heard him saying those comments. And that was anonymous source and I would leave it at that."

She said she did not always agree with her husband's tweets, and that she tells him that. She also said she wished that people would focus on what she does, not what she wears, and then proceeded to pose for pictures in front of some of Egypt's greatest landmarks.

The first lady came in for some criticism back home for her choice of headgear in Kenya. Some commentators said she had made a mistake by wearing a white pith helmet, a hat favoured by 19th century European colonialists, because of its association with the exploitation of Africans.