Michaella McCollum could face another six months in a South American prison, despite moves to bring her home.
Peruvian authorities have agreed to let the 23-year-old, from Dungannon, serve the end of her sentence here but are yet to sign off the paperwork.
Earlier this year, the Co Tyrone woman's repatriation to a Northern Ireland jail was given the go-ahead by the head of the prison service here.
But her return was delayed after Peruvian officials failed to rubber-stamp the documents necessary to facilitate the transfer of McCollum and fellow drug mule Melissa Reid, from Glasgow, according to a source in Belfast.
The pair were arrested at Lima airport in August 2013 as they tried to leave Peru aboard a plane bound for Madrid, with Majorca as their final destination.
They were found with 24lbs of cocaine with a street value of £1.5m hidden inside food packets in their luggage.
The women initially claimed they were forced at gunpoint into carrying the drugs for a South American drugs cartel. However, they later pleaded guilty.
Upon their arrest, their families were warned that their daughters could face up to 15 years in prison. But after a plea bargain, they were convicted in December 2013 and sentenced to six years and eight months in jail.
Both women were then moved from Lima's Virgen de Fatima jail to Santa Monica prison in Chorrillo to begin their sentence, which is due to last until April 2020.
The jail, which is notorious for its crowded and unsanitary conditions, has been used to house foreign female criminals in the past.
Though the Peruvian prison system agreed to let the women see out their sentences back home, a source told an Irish newspaper that the "Peruvians have not done anything with the paperwork that was sent to them from here".
"It was sent over last year but has not come back yet," the source added.
"There is nothing to indicate that it will be done in the coming months.
"There is 50% remission here, but it may be higher for prisoners in Peru, so she may decide to stay there and do the full sentence in Peru so she can get out of jail more quickly."
Michaella turned up in South America two weeks after her family issued a missing person's appeal on Facebook and other social media websites - even securing the support of a number of Irish sport stars.
The photography student had gone to San Antonio in Ibiza in June 2013 on a working holiday, where she was looking for employment as a dancer and nightclub hostess.
Her family said she usually phoned home every two to three days, so they had became concerned when she had fallen out of contact for more than 12 days.