Despite the fact that the couple reported their sighting to the Ocean Club resort, where the McCann family had been staying, police have not yet investigated the incident or called them in to be interviewed.
The witnesses, who did not want to be named, are from south-west England and were visiting relatives Patrick Matthews, 37, and his wife Eliza, 25, in Salema, near Praia da Luz.
The McCann’s official spokesman Clarence Mitchell said that Kate and Gerry McCann were concerned the Portuguese police had not followed up such a “potentially significant lead”.
Over the past few months several witnesses have come forward claiming to have seen young children bearing striking resemblance to Madeline.
Last month a Dutch student told authorities that she saw Madeleine at a roadside restaurant near Montpellier, France.
