Over 100 members of Uganda's biggest opposition party have been charged with various offences including unlawful assembly related to violence around last week's election, according to court documents and an opposition official.

The east African country's veteran leader Yoweri Museveni, 81, was declared the landslide winner of the January 15 poll with 71.6% of the vote against his opponent Bobi Wine with 24%.

Wine, the pop star-turned-politician, and his party, the National Unity Platform have rejected the results, alleging widespread irregularities including ballot stuffing, enforced disappearance of polling agents and intimidation by security forces. Wine's whereabouts remain unknown after he said he had escaped a raid by the military on his home.

In a video on NTV Uganda on Monday night Wine accused police of vandalising his home and said leaving his residence would free him "to speak to the world." He did not disclose his location.

At least 118 members of the NUP were taken to various courts in the capital Kampala on Monday and charged with offences including unlawful assembly, conspiracy and unlawful possession of election materials, NUP lawyer Kato Tumusiime told Reuters and court documents showed.

David Rubongoya, NUP's secretary general, denied their supporters were involved in violent activity.

"Majority of them were polling agents, they even had their letters confirming that they are polling agents of NUP, they were targeted, arrested violently," Rubongoya told local broadcaster NTV Uganda late on Monday.

Scattered protests broke out around the capital on Saturday shortly after the electoral body declared Museveni the winner, although they were quickly quashed by police using teargas and detentions.

Ahead of voting, the UN Human Rights Office accused Uganda's military and police of using live ammunition to disperse peaceful rallies, carrying arbitrary detentions and abduction of opposition supporters.

In power since 1986 and currently Africa's third longest-ruling head of state, Museveni's latest win means he will have been in power for nearly half a century when his new term ends in 2031.