Celestin Mutabaruka, who leads the Fountain Church on Dencora Way, is among five suspects living in the UK. They all deny the accusations against them and any involvement in the killings.
The 63 year old was quoted by the Daily Mirror as saying the claims were "ridiculous" and he was "confident" the inquiry would vindicate him.
He told the newspaper: "To be clear, the investigation is welcome. I'm very happy about it and I have been waiting for it."
One hundred days of slaughter and ethnic cleansing in 1994 left approximately 800,000 Rwandans dead - the majority of whom were Tutsis. Some moderate Hutus also died.
The Metropolitan Police confirmed that its detectives were investigating five men, during the same week commemorations (pictured) were held in Rwanda to make 25 years since the genocide.
They are believed to include Vincent Brown, also known as Vincent Bajinya, 59, from Islington, north London; Celestin Ugirashebuja, 66, from Essex; Charles Munyaneza, 61, from Bedford; and Emmanuel Nteziryayo, from Manchester.
The force said Rwandan authorities referred the matter to its war crimes unit in January last year.
This week, Labour former minister Stephen Twigg called for a "greater sense of urgency" after security minister Ben Wallace said investigations could take between three and five years.
Premier has contacted the family of Mr Mutabaruka for a comment.
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