Clutha-Taieri area response manager Senior Sergeant Alastair Dickie, of Balclutha, said police had recently discovered a collapsible knife ``readily available'' in Balclutha.
The knife can be folded up into a credit card-sized device and could be carried easily
in a wallet or someone's pocket.
Police had discovered at least four people with the knives.
Snr Sgt Dickie said the knife's ability to be easily concealed was a concern and
it could lead to serious injuries.
Police knew of at least one distributor of the knife.
Snr Sgt Dickie said several businesses in Balclutha had been approached to sell the knives.
``If that's the case, we'd like to hear from them.''
He advised anyone who was approached about the knife or knew where it was being sold to report to police.
Snr Sgt Dickie warned anyone with such a knife they could face jail time because possessing it was illegal. They could face up to three years in prison as well as a $2000 fine.
