The guilty pleas made by Michaella McCollum and Melissa Reid have not been accepted because the British women need to provide more information on who supplied the drugs they were found with at Lima airport, prosecutors said.
The two drug mules' guilty pleas have not been fully accepted, as far as the prosecutor is concerned, until they give more details.
They will be asked to give another statement before the judge explaining where the drugs came from, who supplied them and why they said they had been forced to carry them by an armed gang.
More top news
Weather set to stay cool and cloudy tomorrow
Europe's asylum, immigration and freedom of movement laws "wholly inadequate" to deal with arrival of hundreds of thousands of people.
A passenger who helped foil a suspected terror attack on a high-speed train in France is to appear on US show "Dancing With The Stars".