The British government in April announced that it had struck a deal with the Rwandan government to send detainees into the country(Rwanda) in a bid to undermine smuggling networks.
The refugees are being moved against their will, as the UK government is paying Rwanda money to accept them.
The first group is due to be sent on Tuesday 14 June.
The targetted groups are mostly single, young migrants who arrive through “illegal, dangerous or unnecessary methods”, such as on small boats or hidden in lorries.
Prime Minister Boris Johnson said Rwanda would take responsibility for those sent there, with equal access to employment and services.
There is no clear report of how many people could be sent to Rwanda but the prime minister said, people who entered the UK from 1 January could be sent to Rwanda, with no limit on numbers.
Charities and lawyers representing the detainees launched legal action against the UK government and the cases are already in court.
Among the cases, two were heard on Monday where the court of appeal rejected a bid to halt the process.
The charity Asylum Aid has applied for an injunction against the flight, saying the procedure to deport the detainees is unfair because it does not allow enough time to access legal aid and appeal for the right to stay in the UK.
Other human rights groups have questioned whether Rwanda is safe for asylum seekers and say the policy breaks the European Convention on Human Rights.