Police advise Christchurch residents to be aware of bogus tradespeople claiming to be doing earthquake repairs, or giving quotes.
A householder in the suburb of Burnside on Thursday was suspicious of a man claiming to be quoting for roofing repairs.
Because parts of the man's story did not ring true, the homeowner reported the incident to police.
Inspector Paul Fremaux says police regularly hear of similar cases of bogus operators seeking to take advantage of others for criminal ends.
He says residents should report any suspicious activity as quickly as possible. It would be especially helpful if they note vehicle registration numbers or photograph suspicious vehicles.