In a post shared by a NZ Vege Gardeners' administrator, ministry investigator Nick Ward told members not to trade or propagate the seeds without permission.
"Several species of banana passionfruit including Passiflora tarminiana, P. mixta, P. mollisima, and P. tripartita are Unwanted Organisms under the Biosecurity Act 1993.
"Banana passionfruit are considered unwanted organisms because they are aggressive invasive vines that grow prolifically and smother other vegetation."
Biosecurity Surveillance and Incursion Investigation manager Mark Bullians said it was not illegal to possess the plant, just to propagate it and spread it around.
There have been four cases involving either imported seeds or seeds of local unwanted organisms and amateur Facebook gardening groups in the last year.
"Most were addressed with the people involved directly."
Since July 2012 there have been four investigations involving the trade of banana passionfruit.
No one has been prosecuted in the last year, Bullians said.
"The Ministry usually deploys an educative approach in situations like these, looking to a tougher compliance approach should there be a repeat of offending after the person involved had been made aware it was illegal.
"Anecdotally, we believe many people ... remember banana passionfruit from their childhoods and want to relive those days."
In a statement, one of NZ Vege Gardeners' administrators messaged the Herald that the page was full of supportive and passionate vege gardeners, with a broad range of experience.
Members often shared links to ministry information and gave guidance to help protect others and the environment.
They were happy to share information from the ministry so members could make informed choices, the administrator messaged.
