Five siblings, estimated to be between 18 and 25 years old, and a man they identified as their ailing father were found near Ruinerwold, a village in the northern province of Drenthe.

A man who police said had paid the rent on the property was detained, although they could not say on Wednesday whether he was suspected of a crime.

Mayor Roger de Groot had said on Tuesday the 58-year-old was not the father of the family.

"The man is still in custody and is being questioned," said Drenthe police spokeswoman Grietje Hartstra.

"A lot is still unclear and we are investigating exactly what happened there."

The family, who according to local news reports had been waiting for the end of time, was discovered after one member, reportedly a 25-year-old man and the eldest of the siblings, escaped and sought help at a nearby cafe.

Police said they found the family in a "small space in the house which could be locked" and it was unclear whether they were being held against their will.

Officials have not commented on reports the family may have held "end of days" apocalyptic beliefs.

"There is a lot of speculation in the media about what happened but as police we deal with facts. We still have a lot of unanswered questions," Hartstra said.

The children's mother was believed to have died before the family moved to the Dutch farm in 2010, mayor de Groot said.

Dutch newspaper Algemeen Dagblad said the man in custody was an Austrian carpenter identified as "Joseph B.".

It was not clear what his role was or whether he lived on the farm.

The siblings had apparently lived in makeshift rooms inside the farm and survived partly on vegetables and animals from a secluded garden on the property, local TV RTV Drenthe reported.

Australian Associated Press