The Northern Ireland Prison Service must be "cannier" in targeting illicit drugs, the new director general has said.
Sue McAllister said the service needs to build up its intelligence about illegal substances through better relations between warders and inmates.
Prison Ombudsman Pauline McCabe has urged the authorities to do more to tackle the problem after the death of Aaron Hogg, 21, who hanged himself in his Maghaberry Prison cell in May last year after taking a cocktail of drugs.
One solicitor has claimed the high security jail was awash with narcotics.
Ms McAllister said: "With finite resources we need to be a bit cannier about where we target.
"There is a place for random testing and it is a good deterrent but equally we probably should get better at building a rich picture of intelligence trends through knowing what is going on in our jails so that we can target areas for testing."
The 51-year-old mother of two is the first woman to hold the most senior position in the Northern Ireland Prison Service.
She took up post at the beginning of this month and will be paid an annual salary of £100,000, replacing Colin McConnell, who left to become head of the Scottish Prison Service.
Mrs McAllister's last posting was at Onley Prison in Northamptonshire, where she worked on public sector bids to run prisons operated by the private sector. She retired just under a year ago but decided to return to Northern Ireland. She has 25 years` experience in the prison service, including as a governor of a prison and a young offenders' centre.
She was part of a review team which produced a highly critical report on the Northern Ireland Prison Service after the suicide of Colin Bell. Mr Bell killed himself in Maghaberry in July 2008 while on suicide watch.