Two retired detectives searching for Madeleine McCann hope to speak to a convicted paedophile linked to the investigation within the next 24 hours "at the latest", the McCann family spokesman said.
Raymond Hewlett is alleged to have been staying around an hour's drive from the McCanns' holiday flat in Praia da Luz in Portugal when the little girl vanished on May 3 2007.
Clarence Mitchell, the spokesman for Madeleine's parents Kate and Gerry McCann, said the investigators were still waiting for a "definitive response" from Hewlett as to whether he would speak to them.
He added they were spending the night in Germany - where the 64-year-old is in hospital - "with a view to speaking to him tomorrow (Tuesday) morning at the latest".
Mr Mitchell said: "Raymond Hewlett is now well aware that the former detectives searching for Madeleine wish to speak to him as part of their investigation.
"However, the detectives are still waiting for a definitive response from Mr Hewlett. Naturally they hope that he will speak to them.
"If Mr Hewlett is to be eliminated from the Madeleine investigation it is incumbent upon him to speak to the former detectives helping Kate and Gerry in their search."
Mr Mitchell said that by speaking to the investigators Hewlett might help "clear his own name".
UK-born Hewlett, a former soldier who previously lived in Blackpool and Telford, is reportedly being treated for throat cancer in hospital in the German city Aachen.
He was jailed several times for sexually assaulting young girls and is now wanted for questioning by British detectives in connection with a separate indecent assault.