He described him as someone who had been ruled out of the investigation in 2008 but was later jailed for similar crimes in Germany.
When shown a photo of Ney on Spanish TV, Amaral said "it can't be him".
"A paedophile who is German and serving life for killing children has been spoken about," he told a show about missing adults and children," he said, according to The Sun.
"What I know is that the suspect is not him, it's another man. He's also in prison in Germany. He's also a paedophile."
He added that the suspect looks similar to Maddie's father, Gerry McCann.
Amaral was sacked from the case after making the McCann's "arguidos" - official suspects - in the investigation.
He has been involved in a legal battle with the McCann family for years over his book, "The Truth of the Lie", in which he claims that Gerry and Kate McCann covered up their daughter's accidental death in their holiday apartment in Praia da Luz, in the Algarve.
Last year, he claimed MI5 spies had helped to cover up Madeleine's death and disappearance.
The McCanns have continued to insist his accusations have harmed the search for their daughter.