The news comes as it emerged a rift between British and Portuguese officers meant that plans to dig for evidence at sites near the Ocean Complex resort where she was snatched may be delayed.
Sky News crime reporter Martin Brunt said the local press was claiming that Portuguese police had refused to let Scotland Yard search the homes of three men who used to work at the Ocean Complex at the time the three year-old vanished.
He added that the men were "not necessarily" suspects in her disappearance but were potentially linked to "a number of break-ins" in the period before Madeleine disappeared.
Mr Brunt also said that disagreements over leaks to the media may delay planned digging work by detectives working on the case.
He said: "The Portuguese are making it very clear that they were not happy with journalists being briefed.Â
"It's not something that happens in this country and in fact, the Portuguese authorities, according to the Scotland Yard message last night, had threatened to stop any of the work once it begins if they hear that Scotland Yard are talking to reporters."
The Portuguese are making it very clear that they were not happy with journalists being briefed
Mr Brunt said that the row meant digging in three sites near to where Madeleine vanished may not go ahead in the next few days as planned.
Detectives are preparing to excavate up to five sites in and around Praia da Luz in Portugal.
The sites are thought to include wasteland close to the apartment where Madeleine’s family were staying, along with a nearby beach.
Last night, local reports said investigators want to examine roadworks being carried out when Madeleine disappeared on May 3, 2007, which were filled in shortly afterwards.Â
Two areas outside the resort will also be searched in the operation, it was claimed.
Detectives said the searches could coincide with arrests.
Madeleine’s parents Kate, 46, and Gerry, 45, have been fully briefed on the plan by Scotland Yard.