A law expert doubts former Green MP Darleen Tana will be successful in her legal action against her former party

She's trying to stop the Greens' meeting this weekend, where they intend to decide whether to invoke the Waka Jumping law.

Tana's challenge against the party will be heard in the High Court in Auckland this morning.

Otago University Law Professor Andrew Geddis says he's never seen anything like it.

He says the chances of the courts acting in her favour are practically zero.