Britain has suspended aid to Rwanda due to concerns about its role in the conflict in Democratic Republic of Congo.
International Development Secretary Justine Greening said a payment worth £21 million would not be released.
The BBC reports a payment of £16 million was made in September despite questions over Rwanda's support for the M23 rebels in DR Congo.
Ms Greening said fresh evidence presented by UN experts earlier this month about Rwanda's role in the conflict, was "credible and compelling".
However, she said the government would give a further £18 million for immediate humanitarian needs in DR Congo.