Sources close to the families of the 10 people held have told Sky News that a $40,000 (£28,000) demand has been made for their release.
However, the Cambodian authorities allegedly told them they would still not be given their passports and would be obliged to attend a court hearing at a later date.
Members of the group have told relatives that some - although not all - have been informed that, as an alternative, if they confess to the alleged crime they would spend six weeks in jail and then be released upon payment of a fine.
One source close to the families of those arrested told Sky News: "It's extortion, plain and simple. Forty thousand dollars is a lot of money to find.
"There's been no mention to us that it's a bail arrangement... As far as we're concerned, we're being asked for a one-off cash payment to set them free.
"Even if we paid it, who's to say that there wouldn't be another demand for another $40,000 down the line?
"The families are worried sick. These people did nothing wrong, no credible evidence has been presented against them... and now this demand for cash? It's corruption and it's a disgrace.
"While they're being held, they are also being charged $90 for food and $80 for use of electricity."
Five Britons are among the group of 10 arrested in the Cambodian resort of Siem Reap for "singing and dancing pornographically".
Vincent Harley Robert Hook, 35, Daniel Richard Leeming Jones, 30, Thomas Alexander Jeffries, 22, Billy Stevens, 21, and Paul Francis Harris, 32, were arrested along with three other men and two women during a party in the northwestern resort town last Thursday.
The other members of the group are: Job Robertus van der Wel, 22, from The Netherlands; Canadians Jessica Drolet, 25, of Ottawa, and Eden Koazoleas, 19, of Alberta; David Nikolaus Aleksandr Ballovarre, 22, of Oslo, Norway; and 32-year-old New Zealander Paul Martin Brasch.
All have been told they could be jailed for between a month and a year if convicted of a charge "producing pornographic pictures".
Local police have produced photographs showing clothed and laughing tourists, some in sexually suggestive positions.
However, the group insists that none of the people in the images are among those arrested.
Sky News has attempted to contact Cambodian authorities for comment.