The seven will be spoken to by officers between November 24 and November 28 in Faro.
Two women will be questioned - the British one and another of Eastern or Central European origin.
Five men, two British and three Portuguese will also be asked for their whereabouts on the night Madeleine vanished. A further four people will be spoken to as witnesses.
It’s thought three of those being questioned will be declared “arguidos” - or given formal suspect status under Portuguese law.
Some of those being questioned have been spoken to by police before - none were known to the McCanns.
It’s thought some amongst the group may have worked at the Ocean Club around the time the three year old disappeared.
This is the latest stage of the British investigation into what may have happened and follows extensive reviews of mobile phone footage.
Scotland Yard announced last week that they were reducing the number of detectives assigned to Operation Grange. Probably, having sorted out the mobile phone footage, several detectives were left with little to do and so were reassigned. Or, it could mean that the Yard is starting to wind down the investigation, in which case, if these questionings don't produce something tangible, it wouldn't surprise me to see them bring Operation Grange to an end or reduce it to just a couple of detectives.