A Cambodian-Australian grandmother was caught at Sydney Airport carrying more than 252 pellets of heroin inside her last Thursday after arriving on a flight from Phnom Penh.

According to the Australian Customs and Border Protection Service (ACBPS), the 50-year-old has been charged with importing heroin and appeared in court on Tuesday.

She faces a maximum penalty of 25 years in prison and has been released on conditional bail.

Fairfax Media has identified the dual citizen as Lorn Cheng, who spent seven weeks in Cambodia visiting friends and relatives.

“I didn’t know anything; this is such a huge shock, she has never done anything like this whatsoever,” her daughter Brenda told Fairfax.

The last time Brenda heard from her mother, two weeks ago, she had just extended her stay in Cambodia for a week, she said.

The grandmother appears to have ingested the pellets before leaving Cambodia and was detected at Sydney Airport after a baggage scan found ephedrine and cocaine residue in her luggage, ACBPS said.

A body scan then showed “inconsistencies”. Cheng was then taken to hospital and “later passed a total of 252 pellets” of heroin.

“The potential danger this woman has put herself in is a reminder of the risks involved with this kind of concealment,” said ACBPS regional commander Tim Fitzgerald.

Conrad Jensen, acting airport police commander for the Australian Federal Police (AFP), said the arrest should be taken as a “warning” for would-be drug traffickers.

The AFP declined to comment further on drug trafficking into Australia from Cambodia.

A number of significant seizures have been made at international airports here in recent years. In 2014, the US State Department said that Cambodia “has a significant and growing problem with drug consumption, trafficking and production”.

In September 2013, an Australian teacher headed to Australia was arrested with a young Frenchwoman at Phnom Penh International Airport with 2.2 kilograms of heroin. Along with a Nigerian national who allegedly packed the drugs, the trio received sentences of between 23 and 27 years.

Khieu Samon, the Ministry of Interior’s anti-drug police chief, said that he did not have detailed information about the Cambodian-Australian woman’s case.

ADDITIONAL REPORTING BY SEN DAVID