PARIS (Reuters) -A French court will rule on Tuesday on whether Perrier must withdraw its bottled water from shelves, after consumer group UFC-Que Choisir sought an emergency intervention over what it alleges is deceptive marketing of the brand as "natural" mineral water.

The move is the latest development in an ongoing scandal surrounding the Nestle owned brand since French media reported last year that Perrier and many other mineral water producers had been illegally treating their water to prevent contamination.

An inquiry commissioned by France's Senate found in May that the French government had covered up the use of treatments for years.

Nestle said it regretted the use of the treatments and has since stopped using them, switching instead to microfiltration, which it says is safe and does not alter the mineral makeup of its water.

However, UFC-Que Choisir argues that the microfiltration is another kind of treatment that has not been approved by authorities, and given its use to remove contaminants, suggests there could be a potential health risk.

"Perrier waters labelled as "natural mineral waters" are not natural. Nestle has used, and continues to use, illegal treatments for this category of water," UFC-Que Choisir said in June when it brought the case to court.

"We strongly dispute all of UFC Que Choisir's claims," said a Nestle Waters France spokesperson ahead of the decision, expected from the Nanterre judiciary tribunal in the afternoon.

Famous for its teardrop-shaped, green glass bottles, Perrier has been produced from spring water in southern France since the late 19th century and marketed worldwide. Nestle's Waters division has owned the brand since 1992.

In July, Nestle withdrew its 0.2 micron microfiltration in its Vergeze factory after a request from local authorities, and replaced it with a 0.45 micron device, which it already uses for its Vittel water and has discussed with authorities.

The new filtration system is part of a broader dossier awaiting approval from local authorities for its continued production of mineral water at Vergeze.