The chairman of the British Parliament's media committee says a millionaire backer of the successful campaign to leave the European Union has questions to answer about his contacts with Russian officials.

Damian Collins says the Culture, Media and Sport Committee plans to question Brexit backer Arron Banks this week. The announcement follows a report in the Sunday Times newspaper that Banks' contacts with the Kremlin were more extensive than previously acknowledged.

The Times says Banks, who founded the group Leave.EU, held undisclosed meetings with Russian officials around the time of the June 2016 referendum on EU membership. Leave.EU, backed by lawmaker Nigel Farage, operated independently from the official Vote Leave campaign.

Banks called the newspaper's report "a convenient witch-hunt."