(CNN) Vietnam has enacted a catch-all cybersecurity law that could easily be used to ensnare citizen journalists and bloggers, free speech advocates and rights groups warn.

The law, which criminalizes criticism of the government and obliges internet companies to store data locally and hand over user data to the government without the need for a warrant, came into effect on January 1, according to state media.

In an article in the lead-up to the law being enacted, government-run media described the seven-chapter law as one that "(protects) national security and ensures social order and safety on cyberspace, and responsibilities of agencies, organizations and individuals."

In his New Year's Day speech, Vietnamese Prime Minister Nguyen Xuan Phuc said: "Mass communication efforts must be stepped up to create 'social consensus.'

"Those abusing the freedom of information and free speech, causing harm to the interests of the State and citizens would receive appropriate punishments."

'Totalitarian model'

The law has been met with staunch opposition from human rights organizations and online advocacy groups since it passed the National Assembly last summer.

"It really sounds like a very totalitarian model of control of information," Daniel Bastard, head of Reporters Without Borders' Asia-Pacific desk, told CNN.

"The fact that any content deemed opposed to the Communist Party ideology would be suppressed and mostly the authors of this content would be regarded as enemies of the state, it sounds like a very Stalinist model."

The law has been open for public consultation since it passed last year, but Bastard says that, if anything, the law has been made even more draconian since first drafted.

A decree published toward the end of the year to explain how the law would be implemented is "not satisfactory at all," he said.

"The decree was even worse than the draft law. Everything is blurred. How this law will be implemented, we still don't know. The Vietnamese government said that Google is planning to open an office in Vietnam, but this hasn't yet been confirmed, so we're in a very gray area."

He says the law bears striking similarities to oppressive anti-cyber free speech laws in effect in China.

"It's obviously inspired by the Chinese security law, it's a Chinese-like model but in Vietnam (services like) Facebook are not blocked."

He says he doesn't know if the implementation of the law will lead to more sites like the social media giant finding themselves blocked. "We're at a crossroads," he said.

The Vietnamese government did not return CNN's requests for comment.

'Serious concerns'

The law "raises serious privacy and civil liberty concerns for the people of Vietnam and stands to significantly damage the country's economic growth prospects," Jeff Paine, managing director of the Asia Internet Coalition, an industry body, said in a statement when the decree was drafted late last year.

"The overly-broad 'blanket approach' to data localisation requirements will have serious consequences for economic growth, investor confidence and opportunities for local businesses," he said.

Calling the new law's definition of user data "sweeping," Human Rights Watch (HRW) detailed what it said were abuses of internet users' right to privacy. Under the law, internet service providers must "store data locally, 'verify' user information, and disclose user data to authorities without the authorities having to produce a court order," HRW said.

Before the law came into effect, HRW's deputy Asia director, Phil Robertson, said it was "designed to further enable the Ministry of Public Security's pervasive surveillance to spot critics, and to deepen the Communist Party's monopoly on power," adding that "anyone who uses the internet in Vietnam will have zero privacy."

Crackdown

The Southeast Asian country has been intensifying its efforts to stifle online speech.

A popular blogger, Nguyen Ngoc Nhu Quynh, who is known by her online pseudonym, Me Nam -- which translates to "Mother Mushroom" -- was arrested by the Department of Public Security in October 2016, according to the state-run Vietnam News Agency (VNA), which referred to her in reports as an "anti-state instigator."

The blogger, famous for her tagline, "Who will speak if you don't?" was convicted in June 2017 and sentenced to 10 years in prison.

Nguyen, whose blog covered issues such as land confiscation, freedom of speech and police brutality, was released a year and a half into her sentence for "conducting anti-State propaganda" late last year, and granted asylum in the US.

Vietnamese blogger Nguyen Ngoc Nhu Quynh, left, also known as 'Mother Mushroom,' stands trial at a courthouse in the central city of Nha Trang on June 29, 2017.

Following her release and deportation to the US, a State Department spokeswoman told CNN that the US would continue to call on the government of Vietnam to "immediately and unconditionally release all prisoners of conscience and allow all Vietnamese citizens to express their political views without fear of retribution."

The Committee to Protect Journalists, which awarded Nguyen its International Press Freedom Award, asserts that at least 10 journalists were imprisoned in Vietnam as of December 1, 2017 -- a figure that, at the time, included Nguyen.