The Wyllie family have been unable to help authorities investigating the disappearance of Madeleine McCann, the Wyllie Group says.

Private detectives searching for Madeleine wanted to interview the widow and daughter of WA property tycoon Bill Wyllie amid claims their yacht was moored in Spain three days after the British girl’s disappearance.

About the same time, a woman aged in her 30s with an Australian or New Zealand accent reportedly asked a British businessman at the marina if he was there to “deliver my new daughter”.

The family's company, the Wyllie Group, dismissed the claims in a statement.

"British media reports on Sunday … raised suggestions that Wyllie family members may be able to assist investigators in relation to an incident at Port Olympia, Barcelona, on the night of May 6, 2007," the statement said.

"The Wyllie family is perplexed with these media reports. In fact, members of the Wyllie family were in Antibes, France, that evening, not in Barcelona.

"The Wyllie yacht, Willpower, was docked in Port Olympia on May 6, 2007, crewed by American and English personnel.

"The Wyllie family appreciates that the McCann family needs to pursue every possible inquiry and will co-operate with police investigators to confirm any facts."

Private detectives working for Madeleine’s parents wanted to speak with Rhonda Wyllie and her daughter, 31-year-old Melissa Karlson, to find out why the vessel was in Barcelona and if either woman was travelling aboard.