Rwandans have voted in favour of constitutional change to enable President Paul Kagame to seek a third term in office, according to preliminary referendum results.

The National Electoral Commission announced Friday night that 98 per cent of Rwandans had voted “Yes” from results recorded in 21 of the 30 districts, representing a tally from 70 per cent of the country.

Final results are due Monday but nothing is likely to change after all polling stations recorded above 90 per cent for the ‘Yes’ vote, including close to 40,000 Rwandans in the diaspora who also voted Thursday in favour of the Constitution amendment.

Kicukiro District (one of three districts that make up the capital - Kigali Province), recorded the highest disapproval with 8,114 residents, a 4.11 per cent, voting against the changes.

Kayonza District in the Eastern Province recorded the highest approval with 99.23 per cent of 191,828 Rwandans voting yes.

About 6.39 registered voters were expected to participate.

Under the revised law, President Kagame is eligible to run for office in 2017 for another "transition" term of seven years, as well as two more five-year terms.

The United States and the European Union have come out against the move to amend the Constitution, which they say is intended to secure the incumbent’s longevity in power. They said it undermines democratic principles.

The EU delegation in Kigali on Friday raised concerns over lack of independent monitoring, noting that Rwanda did make necessary provisions for the international community to observe the elections.

The current constitution limits the president's tenure to two seven-year terms, of which Kagame is serving his second and final, scheduled to expire in 2017.

READ: Kagame could rule until 2034

President Kagame has continued to deflect questions about his third term bid, leaving the country and the international community guessing, though there is wide expectation that he will.

He has been the president of Rwanda since 2000, taking over from Pasteur Bizimungu who resigned after five years as head of state.