Woma pythons, a spotted python and frilled-neck lizards are among the reptiles stolen in a break-in at a nature reserve.

Thieves broke into the Blackbutt Reserve at New Lambton in Newcastle over two nights, on Friday and at about 1.30am on Sunday, taking off with almost the entire reptile collection, leaving behind just one reptile, Newcastle City Council said.

One of the frill-neck lizards stolen from the Blackbutt Reserve. Credit:NSW Police

"On both occasions entry was forced to a storage room," NSW police said.

"A frill-neck lizard was stolen on the first night and 15 reptiles were taken last night."