The remains of a girl, aged between two and four, were found next to a motorway near Adelaide earlier this month.
The Met said it was "aware of reports" and had made contact with authorities.
Australian Police Commissioner Grant Stevens said there was "no evidence" the body was Madeleine's.
Madeleine was aged three when she went missing from her family's holiday apartment in Praia de Luz, in Portugal's Algarve, in May 2007.
Reports in Australia suggest the decomposed body was that of a young girl - believed to be fair-haired - who was killed at least as long ago as 2007.
The remains were discovered in a suitcase next to a remote motorway in Wynarka, in South Australia, earlier this month, local police said.
Australian authorities have so far been unable to identify the girl.
However, Mr Stevens told a parliamentary estimates committee hearing: "There is absolutely no evidence at this point in time that the child is Madeleine McCann.
"To suggest something like that at this point in time would purely be speculating to get attention.
"We are focusing our inquiries on South Australia but we would be considering any potential missing child.
"Until we ascertain the identity of the child we need to be open to all possibilities."
Last year, detectives from London flew to the Algarve to assist with searching scrubland near the resort where Madeleine disappeared. They did not uncover any evidence.
Portuguese police questioned 11 people as part of their investigation.
The Met's Operation Grange was set up in 2011 after Prime Minister David Cameron asked the force to "bring their expertise" to the inquiry following a request from Kate and Gerry McCann, Madeleine's parents, who are from Rothley, Leicestershire.
Police investigating the disappearance of Madeleine McCann have contacted authorities in Australia following the discovery of a girl's remains in a suitcase, Scotland Yard has said.