Five TikTok users are calling on a federal court to overturn Montana's overall ban on the video sharing app, arguing that it violates their free speech rights.

The lawsuit was filed just hours after Montana Governor Greg Gianforte signed the unprecedented prohibition into law on Wednesday.

Gianforte said on Twitter that he endorsed the ban in order to "protect Montanans' personal and private data from the Chinese Communist Party."

The state is trying to exercise national security power that only the federal government can wield and is violating free speech rights in the process, the suit argued.

"Montana can no more ban its residents from viewing or posting to TikTok than it could ban the Wall Street Journal because of who owns it or the ideas it publishes," the lawsuit argued.

The app is owned by Chinese firm ByteDance and is accused by a wide swath of US politicians of being under the tutelage of the Chinese government and a tool of espionage by Beijing, something the company furiously denies.

Plaintiffs named in the suit included a former US Marine Corps sergeant, a mother living with her family on a ranch, a businesswoman who sells swimwear, and a student who posts video snippets about her outdoor adventures.

The TikTok creators have significant followings and make money from the platform, according to the suit.

The suit calls for the court to stop Montana from enforcing the ban and to pay the legal costs of the plaintiffs.

Montana became the first US state to ban TikTok, with the law set to take effect next year as debate escalates over the impact and security of the popular video app.

The prohibition will serve as a legal test for a national ban of the Chinese-owned platform, something that lawmakers in Washington are increasingly calling for.

The ban makes it a violation each time "a user accesses TikTok, is offered the ability to access TikTok, or is offered the ability to download TikTok."

Each violation is punishable by a $10,000 fine every day it takes place.

Under the law, Apple and Google will have to remove TikTok from their app stores and companies will face possible daily fines.

The ban will take effect in 2024, but be voided if TikTok is acquired by a company incorporated in a country not designated by the United States as a foreign adversary, the law reads.

The law is the latest skirmish in duels between TikTok and many western governments, with the app already banned on government devices in the United States, Canada and several countries in Europe.

gc/caw