The police team searching for the remains of Ben Needham have been asked to stop excavation work.
Detectives on the Greek island of Kos have been approached by the owner of farmland officers are examining following the discovery of ancient tombs.
Detective Inspector Jon Cousins, leading the search, said so far an official court order has not been made.
But if Greek magistrates stop the dig he will mount a legal challenge.
Ben has been missing for 25 years after disappearing while playing outside a farmhouse his grandfather was renovating in July 1991.
His family always thought he had been abducted, but detectives are now working on the theory that the Sheffield toddler, who was 21 months old at the time, may have been accidentally crushed and buried by a digger clearing a building plot nearby.
A 19-strong search team has been examining a site since Monday, with a second site also cordoned off and ready to be excavated.
DI Cousins said: "I was approached on September 29 by the owner of the land on which we are currently conducting the search to find answers for Ben's family and the people of Kos.
"He raised with me concerns about the discovery of what appear to be ancient tombs. So far I have not had any contact from the magistrate to say that we must stop conducting the important work we are doing on site.
"My priority is to ensure that disruption to the operation that my team are running remains at an absolute minimum.
"If magistrates' permission is withdrawn, it will be my intention to seek immediate judicial authority to search this area of land."