The search was requested after German authorities said a suspect in the disappearance of the girl has visited the area.
Portuguese police investigating the disappearance of Madeleine McCann are planning to carry out new searches at a dam about 50km from where she disappeared, according to local media.
A search of the Arade dam will begin on Tuesday. An investigation has been taking place involving Portuguese, English and German authorities.
Christian Brueckner, 45, was made a formal suspect, or an “arguido”, by Portuguese prosecutors in 2022. The search is reported to have been requested by German police as it was an area he had visited.
Madeleine McCann, who was almost four years old at the time, disappeared from her room at the Praia da Luz hotel complex, a small seaside resort in the Algarve region, on 3 May 2007, while her parents were having dinner with friends at a nearby restaurant.
The Portuguese police closed the case in 2008 after 14 months of controversial investigations.
After spending two years studying the case, the United Kingdom officially opened its own investigation in July 2013. The Portuguese authorities reopened their case again shortly thereafter.