The decision was made by prosecutors on the recommendation of police, CNN reported. It follows a report by a cold-case squad with London's Metropolitan Police of new leads in the case after reviewing the Portuguese investigation that was closed in 2008.
Madeleine was 3-years-old when she disappeared from her parent's holiday apartment at a Portuguese beach resort, Praia da Luz. Her parents, Kate and Gerry McCann, had left their children sleeping while they ate with friends at a restaurant within sight of the apartment.
Assistant Commissioner Mark Rowley of the Metropolitan Police said London and Portugal have a "shared determination" to find out what happened to Madeleine.
"This new momentum is encouraging, but we still have a way to go, and as with all major investigations, not all lines of inquiry that look promising will yield results," Rowley said.
The McCanns, both doctors in Leicestershire, said last week that the discovery of a girl who had apparently been kidnapped and was living with a Roma couple in Greece had given them new hope that Madeleine is still alive.