Melissa Reid, 20, was caught along with her friend, Northern Irish-born Michaella McCollum, 20, with 24 pounds of cocaine in their luggage in Lima Airport on 6 August.
The two women admitted drug trafficking charges at a hearing on Tuesday and offered details of others involved in the hope they could avoid a trial and prison sentence of up to 15 years.
They had expected to receive a reduced sentence of a minimum of six years and eight months in prison as a result of their guilty pleas.
But last night anti-narcotics prosecutor Juan Rosas said the pleas would not be accepted by the prosecution unless the pair said they made up their original story.
The women had previously insisted that they had been kidnapped and forced to smuggle the drugs by armed gangsters.
Rosas said that in order for proceedings to be concluded quickly both women must accept full responsibility.
Mr Rosas said: “A new statement is required by the women and they will have to admit not only that they came here to traffic drugs but also that they did not tell the truth with respect to them being kidnapped, they have to make a full admission of responsibility for all of the charges brought by the prosecution”.
He added: “If they continue to maintain this incredible version of events then the prosecution is not going to accept them taking advantage of a quick conclusion of proceedings.”