Britain has already paid Rwanda £120 million ($144 million) to take migrants despite the deal being grounded by legal challenges.
Officials for the east African nation's government confirmed it has received the entire initial payment for the agreement signed in April.
Last month Downing Street conceded that some cash had been paid but refused to say how much or when this had happened, saying the information was "confidential."
The first deportation flight was grounded in June after a series of legal challenges and another attempt is yet to scheduled.
When asked by reporters how much money had already been paid by Britain, Rwandan government spokeswoman Yolande Makolo said: "There was an initial transfer of £120 million. This has already been paid and we are already using the funds to prepare."
Rwanda remains "committed" to the partnership, she added.
Several asylum seekers, the Public and Commercial Services union and charities Care4Calais, Detention Action and Asylum Aid are challenging the legality of the Home Office policy, with the next court hearings due in September and October.
The ongoing court cases have raised the prospect that a flight may not be attempted again until the winter.
Some migrants issued with Rwanda removal directions have already been released from immigration detention because, as yet, another flight has not been lined up.
Earlier this week the Commons Home Affairs Committee found there is "no evidence" that the policy is acting as a deterrent.
Since Home Secretary Priti Patel signed the deal, more than 1,000 migrants have crossed the Channel.
