A $2 million a year crackdown on drugs by the Corrections Department is paying dividends with prisoners having the toughest time getting drugs behind bars.
Half of New Zealand's inmates have substance abuse problems and Corrections takes every precaution in a bid to keep drugs out of prisons.
"Prisoners will continue to try to use them and try to fight our systems. Our job is to try to minimise that as much as possible," chief custodial officer Neil Beales says.
When random drug testing was introduced back in 1998, 30 per cent of inmates were using but that is now down to just five per cent or 700 inmates.
"We use things like drug detector dogs and CCTV. We have good operational intelligence and we work with police," says Mr Beales.
Cannabis is the most popular drug of choice behind bars at 87.2 per cent, followed by the methamphetamine and ecstasy.
Drug rehabilitation programmes are offered to inmates so they can leave drug free.
"For me to be able to stand here and say to you by this time next year we're going to have zero drugs in prison, I've been around long enough to know that's not likely to be the case. But it doesn't stop us from continuing to work hard to reduce that supply," says Mr Beales.
Random drug tests were extended to the 8,000 Corrections staff in 2013. Just 26 tests were carried out last year with two testing positive for cannabis.
"Although it's too small a number of to provide any meaningful results, two out of 26, that's a worry if it indicates that percentage of staff are actually smoking dope," says Roger Brooking a drug and alcohol counsellor.
But Mr Beales says Corrections has got a good recruitment process.
"We have a zero tolerance for that. Absolutely zero tolerance, integrity is important," he says.
Mr Beales hopes that integrity helps inmates start life on the outside clean. And he says $2 million spent on drug testing is small coin when you're turning people's lives around.