The anti-corruption group, Transparency International Vanuatu, says the Government must redraw a raft of planned constitutional changes.
Last year the Government passed amendments to increase the size of Cabinet, stop the movement of MPs between parties, restrict opportunities for votes of no confidence and extend the parliamentary term.
But the changes were ruled unconstitutional by the Vanuatu Court of Appeal.
The Government is believed to be planning a public referendum on the amendments, but spokesperson for TIV, Marie-Noelle Ferrieux-Patterson, says the law changes must be re-written, with input from the people.
"They were sneaked in by the back door of the Parliament a week before they were presented in Parliament. Most Parliamentarians had not even looked at them before they sighted them in Parliament. So considering that the amendment is not only unconstitutional but is fundamentally tainted, the Government should go back to the drawing board - not only the drawing board but also have a consultation with the people."