Officers swooped on a house near Gin Gin, 370 kilometres northwest of Brisbane, after a tip-off that children were born in secret and their bodies hidden on the property by the same family in the 1990s and early 2000s.
"I can confirm we are conducting investigations into information received regarding allegations a number of child births have been concealed on the property," said cold case homicide Detective Inspector Mick Dowie.
"We will be interviewing a number of persons who may also be able to assist with our investigations over the coming days."
"There's one family involved," Dowie added, without saying whether they were cooperating with police.
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"You can draw your own conclusions from the fact that we're doing an excavation."
Given the potential remains are more than a decade old and tiny, he said the excavation process was "meticulous".
"The scientific examination and excavation is a meticulous and time consuming process," Dowie said in a later statement after a day of searching.
"Some items have been seized, however no skeletal remains have been located or any items that in isolation provide evidence that could corroborate the information we are investigating."
Gin Gin councillor Wayne Honor said the small community, with a population of less than 1,000, was in shock.
"We just hope (police) can come to an outcome that is going to give and let our community come to a little bit of peace," he told the Australian Broadcasting Corporation.