NEW ZEALAND - The Corrections Department is claiming a big win in its war on the smuggling of weapons and drugs into the country's jails.

A new blitz doubled the number of seizures of two years ago uncovering some bizarre and frightening weapons.

More than 1,500 illegal items were seized on prison grounds last year - double the amount intercepted in 2003.

Much of the contraband relates to drugs like cannabis and methamphetamine. But smuggled weapons pose a serious safety threat to inmates and staff.

Ten years ago, two officers were stabbed and a third slashed with a bayonet smuggled into Christchurch Prison.

Prison bosses credit new video surveillance, metal-detecting technology and drug dog teams for the success.

But, the prison officers' union says while the interception rate is encouraging, more needs to be done.

"They're not always being brought in, they're made within the system, you'd be surprised what can be made into a weapon," says Beven Hanlon of the Corrections Association.

While inmates and visitors are the main smugglers, figures obtained by One News show three prison staff have been dismissed for bringing in contraband.

Last year the government earmarked an extra $4 million over four years for drug and weapon detection. The Corrections department says the increase haul of weapons is proof it was money well spent.