The police are continuing to look for a radioactive instrument which was inside a vehicle that was stolen in Christchurch.
The nuclear density meter was in the back of a white Ford Courier ute when it was stolen from New Brighton on Tuesday.
The police say anyone trying to remove the radioactive material could receive deep sunburn-like injuries.
The instrument is bigger than a tool box, and is used by roading contractors. It measures soil density and moisture content, and contains two small radioactive sources inside stainless steel casing.
Inspector Marc Paynter from Police National Headquarters says the machine is safe unless it is tampered with.
"There would be a health hazard if anyone tries to use the machine because it emits radiation when it is in use, or tries to dismantle the machine which might expose the radioactive source."
Tony Cotterill, of ESR's National Radiation Laboratory, says the instrument has a number of markings on the outside, including UN332 and a radiation warning sign.
He says anyone who finds the instrument or something that looks like it should call the police immediately.
Mr Cotterill says there are currently more than 100 nuclear density meters in the country.