Plans to convert a defence site into a freight hub in Sydney's south-west can proceed, provided developers implement strict conditions to protect a rare flowering plant, the Land and Environment Court has decided.

The discovery of 370 individual Hibbertia fumana plants - a species last documented in 1823 and long thought extinct - threatened to stall development of the $1 billion-plus Moorebank Intermodal Terminal Facility.

Thought to be extinct for almost 200 years, the newly named Hibbertia fumana has made a comeback. Credit:Via Nature Conservation Council

The court imposed conditions on the project, which will be finalised in about a week. According to the earlier agreed conditions, Qube, the developer, will be required to develop a Hibbertia species survey plan to assess the number of individual plants within the rail corridor.

A disused rail spur traversing the Southern Boot Land must also be removed and remediated.