However, the Wildlife Enforcement Group is "reasonably confident" the flow of endemic reptiles out of New Zealand has declined to a "slow trickle".
"It's a lot better than it was in the early part of 2000."
While not prepared to give the price geckos fetched in Europe, he said it was in the "thousands and thousands of dollars".
Worldwide, the illegal trade in wildlife was estimated by Interpol to be worth $US7 billion to $US10 billion.
New Zealand's reptile species were unique because they gave birth to live young rather than laying eggs and due to their colour, the jewelled ones especially, he said.
While reptiles were the main target, there was a growing market in endemic invertebrates, such as wetas, and interest in New Zealand's orchid species.
He hoped to increase awareness of this issue in Dunedin this week, by speaking to community groups and people with an interest in wildlife.
Landowners and operators on the Otago Peninsula needed to be aware people who turned up on their property might not be what they seemed, he said.
"The great majority of European [tourists] are genuine, but there is an element of others coming."
The Wildlife Enforcement Group is funded and staffed by New Zealand Customs, the Ministry of Agriculture and Forestry and the Department of Conservation.
It had the task of preventing the organised illegal trade of flora and fauna.
The group and its officers were reliant on good information from members of the public, landowners and experts to build up intelligence on likely targets or offenders, Mr Hitchcock said.
He could be contacted on weg@iconz.co.nz.
Penalties for those caught varied, with the most recent gecko smuggler being fined $12,000 and a bird egg importer $20,000.
