Rwanda says UN agency 'lying' over UK deportation plan

President Paul Kagame. [AFP]

Rwanda on Wednesday accused the UN refugee agency of "lying" after the body alleged in court that asylum seekers sent to the East African nation from the UK could be resettled again and face persecution.

Britain's controversial plan to deport migrants to Rwanda has been mired in legal challenges but Prime Minister Rishi Sunak's government has insisted it will proceed if his Conservative Party wins a July 4 general election.

On Monday, lawyers with the United Nations High Commissioner for Refugees (UNHCR) told the High Court in London that individuals under the scheme faced being moved on by Rwanda to a different country where they could face violence or persecution, in a process known as refoulement.

"UNHCR is lying," the Rwandan government said in a statement, accusing the agency of making "a series of wholly unserious allegations" against Kigali.

"The organisation seems intent on presenting fabricated allegations to UK courts about Rwanda's treatment of asylum seekers."

Monday's hearing in the UK - where the UN body made a successful bid to intervene -- is the latest in a string of legal challenges dogging the initiative.

"The UNHCR has been consistently clear on its concerns regarding the serious risks that 'externalization' poses to refugees, including refoulement, and finds that the UK-Rwanda Asylum partnership shifts responsibility for making asylum decisions and for protecting refugees," the UNHCR said in a statement later Wednesday, declining to comment further.

Britain's ruling Conservatives say the deportation scheme is designed to deter migrants from attempting to cross the Channel to the UK from northern France, with Sunak stating it will start in early July.

However, opposition Labour leader Keir Starmer has promised to ditch the plan if his party wins the July 4 election.