Europe could face a new wave of migrant arrivals this summer, a leaked German government report has warned. Up to 6.6m people are waiting in countries around the Mediterranean to cross into Europe, according to details of the classified report leaked to Bild newspaper.

They include more than 2.5m in North Africa waiting to attempt the perilous crossing by boat. Angela Merkel’s government has not commented on the report, which the newspaper says was marked for internal use only.

There are fears of a dramatic rise in arrivals as the summer weather turns favourable for sea crossings. Growing numbers of migrants are known to be attempting to reach Europe by boat in the wake of the closure of the Balkan land route last year.

They include refugees fleeing the turmoil in Syria and Iraq as well as economic migrants from Africa, the Middle East and Asia. The report warns the number waiting to cross into Europe has risen by 650,000 since the end of January alone — an increase of 12 per cent.

It says 1m are waiting in Libya, where smugglers use small and often unseaworthy boats to carry migrants to outlying Italian islands. Another 1m are waiting in Egypt, 430,000 in Algeria, 160,000 in Tunisia, and 50,000 in Morocco. Others are waiting in transit countries along the route, with up to 720,000 in Jordan.