Britain has asked the Ugandan government to speed up investigations into claims of intimidation and continued harassment of opposition figures, barely a week after the country held its contested presidential election.

UK Foreign Secretary Dominic Raab, who is in Nairobi on an official visit, said the UK government was closely monitoring the situation in Uganda after claims that the main opposition figure, Bobi Wine, was placed under house arrest.

Raab, who was speaking to journalists on Wednesday, said the investigations should be done in a transparent manner and that anyone found culpable held to account.

The Foreign Secretary was responding to questions on the UK’s position on the aftermath of the poll that has seen mounting tension between the government and opposition leaders in the East African country.

“We are aware of the concerns and the issues that have been raised and we expect them to be transparently reviewed and investigated by Ugandan authorities…the UK’s view is that there should be transparency and accountability and if there are irregularities learnt then they must be accounted,” said Raab.

Wine, who lost the January 12 election to incumbent President Yoweri Museveni, has accused the Ugandan leader of intimidating his family by placing them under house arrest.

On Monday, Wine added that his family was running out of food, four days after the military surrounded his home and restricted their movements.

The former pop-star turned politician also accuses the military of harassing his family and denying him access to visitors, including US ambassador Natalie Brown.

Wine received 34.83 per cent of the votes, after running a campaign against constant police harassment and violence. He rejected the results, citing fraud and massive rigging.

76-year-old Museveni, who won a sixth term in office, has been accused of using the police and army to intimidate his opponents, and resorting to violence to silence critics, claims he denies.

But despite the loss, Wine, whose real name is Robert Kyagulanyi, continues to emerge as one of the country’s most consequential opposition leaders with growing popularity among the urban youth.

Wine’s National Unity Party (NUP) won 61 constituencies in parliament, making it the second most popular party in Uganda’s 11th parliament, despite being the youngest political movement in the country.

The Forum for Democratic Change, the country’s main opposition party, secured 21 seats -- 15 less than in the 10th parliament.

But Museveni, who has since the early 2000s faced a growing opposition from a section of leaders in the country, says the resentment against his leadership was being propagated by populist leaders with no agenda for the country.

The Ugandan leader has survived a strong opposition wave before, often through cracking down on dissent.