Police are investigating the theft of seven geckos in a smash and grab raid at the Whangarei Museum and Heritage Park on Monday night.
Park director Sue Walters says the thieves appear to have jumped over the fence.
She says there is a black market for geckos but a smuggling them overseas would require the thieves to have a sophisticated network of connections.
Park staff have notified the Wildlife Enforcement Group, which includes staff from a range of government agencies. The park's lizards will be kept permanently indoors as an added security measure.
In a similar theft in 2006, four geckos were stolen from the museum, prompting a customs alert.