Some 3.6 million refugees are expected to arrive in Germany by 2020, government sources told Sueddeutsche Zeitung (SZ).
Sources at the Ministry of Economic Affairs and Energy told the newspaper they arrived at their estimate liaising with other government departments as part of their predictions for the country's economic development.
More than a million refugee refugees and migrants entered Germany in 2015, with many parts of the country struggling to cope with the influx. The figures are based on a further half a million people arriving in the country every year by the end of the decade.
Officials told the newspaper that the government faced having to cut budgets despite record tax receipts because of the number of refugees expected to arrive. Junior finance minister Jens Spahn told the newspaper the record €19.4bn surplus taken by the government in 2015 in taxes is "by law completely reserved for financing the refugee crisis".
With European populations ageing and growth sluggish, some economists believe that the intake of refugees could boost European economies.
On Thursday, 25 February, the German Bundestag will vote on a new bill allowing authorities to deport immigrants unlikely to be granted asylum more easily, and tightening rules allowing families to join those who have travelled to the country.