Michaella McCollum Connolly and Melissa Reid have been sent to prison to await their trial on drug trafficking charges.
A Peruvian judge, Dilo Huaman, rejected the defense team's claims that they had been threatened with death if they had refused to carry the 11 kilos of cocaine out of Peru and refused bail.
No trial date has been given.
Michaella McCollum Connolly, 20, from Dungannon, Co Tyrone, and Melissa Reid, 20, from Glasgow face a maximum sentence of if 15 years if convicted of trafficking cocaine worth almost $3 million, the Irish Times reports.
In a brief statement the country’s state prosecution service said: “The Callao state prosecutor’s office has filed a criminal suit before the courts against Michaella McCollum Connolly and Melissa Reid as suspected authors of a crime of drugs trafficking using transport.”
It said: “State prosecutors have gathered enough evidence pointing to the alleged responsibility of both women, which means that in the course of the investigations against them conducted so far, the allegations against them have not changed."
The two women were pictured Tuesday in handcuffs being escorted by officers from the National Police anti-drug headquarters for medical examinations.
Two weeks ago, on August 6, Peruvian police discovered over 11kilograms of cocaine hidden inside food packages as the women attempted to board a flight from Lima to Madrid.
Both women have denied both allegations and claim they were forced to carry the bags by armed men.
On Tuesday McCollum's lawyer Peter Madden denied media reports of his client's alleged involvement with drugs.
"Michaella McCollum did not owe any money to any drugs dealer, she was not and is not involved in the drugs trade, she has no criminal record, she has never been in trouble with the police in her life," he said.
"She was not seen on video carrying drugs, as was alleged in one newspaper, she was carrying a handbag, it was her handbag, it was pretty obvious it wasn't drugs, but that was the report.
"She was not out shopping in Lima and spending a lot of money, that didn't happen."
He said the women were being kept in harsh conditions but were being treated well.
"They are fairly tough conditions, there's not an awful lot to eat there, but she's been treated fairly well by the police and by the people in the police centre," he said.
He added: “Each time I see them they are getting more and more worried.”
“I know they were very frightened today, because they were put into a very small confined area with pretty Spartan conditions.”