They were arrested in Kalangala in central Uganda but no details of the arrest are available.
Uganda opposition presidential candidate Robert Kyagulanyi, popularly known as Bobi Wine, and his campaign team have been arrested in the country's central region, he said on Twitter.
No further details of their arrest were immediately available. They were arrested in Kalangala in central Uganda, Wine said in the post.
Joel Senyonyi, spokesman for Wine's party, the National Unity Platform, said: "Yes police has arrested him together with his whole campaign team. They (police) put them in police trucks and started driving but we don't know where they are taking them."
Police spokesman Fred Enanga was not immediately available for comment.
Wine has emerged as the strongest challenger to President Yoweri Museveni, 76, in the presidential election on January 14.
In November, at least 54 people died after protests erupted following Wine's brief detention over alleged violation of Covid-19-related social distancing measures.
Police said at the time they had arrested nearly 600 people and accused protesters, whom authorities had enlisted the help of the military to disperse, of rioting and looting.
On Tuesday, United Nations human rights experts called on Uganda to rein in violent security forces and drop charges against political opponents and activists arrested in what the experts called an election clampdown.
On Sunday Wine, whose real name is Robert Kyagulanyi, said one of his bodyguards was killed when military police ran him over while Wine's convoy was taking a wounded journalist to seek medical help.
Military police said the bodyguard had fallen from a speeding car.
"We are gravely concerned by the election-related violence, the excessive use of force by security personnel, as well as the increasing crackdown on peaceful protesters, political and civil society leaders and human rights defenders," the UN experts said in a statement.
Both the president's and government's spokesmen declined to take calls from Reuters seeking comment.