Wildlife smugglers are "greedy people without any consideration for animals", Wildlife Enforcement Group senior investigator Stuart Williamson says.
He believes more people are illegally taking New Zealand's endangered wildlife than officials here are aware of or can tackle.
The Department of Conservation says jewelled geckos are highly sought after by reptile collectors in Europe, with individual animals changing hands for more than 5000 ($NZ9200).
After the return of 16 jewelled geckos taken last year in another case, a number have disappeared with some being advertised for sale on European websites.
Mr Williamson's comments followed the appearance of two German men in the Dunedin District Court on charges relating to the illegal international trade of jewelled geckos.
The penalties under the Wildlife Act of up to $100,000 fine and six months' jail did not seem to deter offenders. Despite four men, after two separate incidents, being sentenced last year to up to 14 weeks' jail, wildlife smuggling was still happening, he said.
"A year later, people are still doing it. They are not deterred by going to prison or fines."
Those involved in protecting wildlife were doing their best to show the judiciary the gravity of the situation and the need for severe sentences, he said.
A spokesman for Conservation Minister Kate Wilkinson said a proposed Conservation Bill would increase the penalties under the Wildlife Act.
The penalties being proposed were a maximum of three years in prison, a fine of $200,000, or both, for exporting, or possessing for the purposes of export, absolutely protected wildlife.
Mr Williamson said while those involved in the illegal trade of geckos apprehended in New Zealand came from a variety of countries, those from Germany had been involved in three recent cases.
In Germany, there were nearly 40 shows and fairs a year for people interested in reptiles, far more than other neighbouring countries, he said.
"There seems to be a high interest in that country [in] reptiles."
Collectors were not always rich, but could simply be "everyday" people living in apartments with limited space for a pet like a dog, but room for a small terrarium.
There appeared to be trends in the types of reptiles that were popular, but the jewelled gecko was sought because it gave birth to live young, was highly coloured and active during the day.
"They're unique and really, really interesting, which creates demand".
How much these reptiles were worth depended on the buyer. Wildlife authorities were often reluctant to put a price on their heads in case it led to more cases.
"They're just greedy people who have financial gain foremost."
Otago conservator Marian van der Goes said Doc was always looking at ways to protect species, but the best protection "in situ" was for people in the area to be aware of what was being targeted and to keep a "watchful eye".
The recently released jewelled gecko community management plan showed strong dedication from the Otago Peninsula community to be additional "eyes and ears" when suspicious people were about, she said.
RECENT CASES
• January 2010: Hans Kubus, hunting absolutely protected wildlife under the Wildlife Act (two charges), trading exploited species under the Trade in Endangered Species Act (five charges); fined $5000, 14 weeks' imprisonment (concurrent) on the two wildlife charges.
• March 2010: Manfred Bachmann, possessing absolutely protected wildlife under the Wildlife Act, 15 weeks' imprisonment; Thomas Price, unlawfully possessing geckos, 18 weeks' imprisonment; Gustavo Toledo-Albarran, hunting geckos, 18 weeks' imprisonment.
