Biosecurity officers have returned to the Auckland Botanic Gardens to investigate alleged illegal plant imports.
Gardens' curator Jack Hobbs confirmed Ministry of Primary Industries officials visited the gardens two weeks ago, to view the same plants they had taken samples from when the gardens were raided at dawn by officials six months ago.
The gardens, as well as the homes of Hobbs and veteran Albany ecologist Graeme Platt, were subjected to simultaneous raids last October.
The officers were looking for evidence of agathis silbae, an exotic member of the kauri tree family native to several Pacific islands which may have been illegally introduced, and took plant samples and computers. The raid followed one in February on the rural Wanganui property owned and run as Paloma Gardens by Clive and Nicki Higgie.
The Higgies, Platt and Hobbs deny wrongdoing and no charges have been laid.
Ministry spokesman James Sygrove said investigations were ongoing. "Both are serious, complex and time-consuming.