Ten press freedom groups have signed a joint letter calling for Pham Minh Hoang's release
The letter to Nguyen Tan Dung, published on the Index on Censorship website, was also signed by nine other bodies including Reporters Without Borders, the Committee to Protect Journalists (CPJ) and PEN International.
Hoang, who has dual French-Vietnamese citizenship, was sentenced to three years in prison and a further three years of house arrest in August, after a judge ruled that his articles "blackened the image of the country", according to the letter.
As well as a well-known blogger, Hoang is also a lecturer in applied mathematics at the Ho Chi Minh City Polytechnic Institute and an activist who has worked to promote human rights.
"We would like to remind the Government of Vietnam that Mr Hoang’s blogging activities, as well as his activism, are guaranteed by the Universal Declaration of Human Rights, the UN Declaration on Human Rights Defenders, and the International Covenant on Civil and Political Rights, to which Vietnam is a party to, as well as by Articles 35, 50, 53, and 69 of the Vietnamese Constitution," the organisations said in the letter.
"We call on Vietnamese authorities to recognize Mr. Hoang’s right to expression, and to lift any charges or convictions related to his protected expressive activities, and — with these charges lifted — to ensure his release."
The letter to the Vietnamese prime minister comes as the CPJ called on the government to "immediately and unconditionally" release all of the journalists detained in the country.
According to the press freedom group in the past six months at least nine journalists, most working largely online, have been jailed.
"With these arrests, Vietnam now ranks among the worst jailers of journalists in the world," Bob Dietz, CPJ's Asia program director, said in a report.
"The crackdown under way underscores the Communist Party government's enduring fear of an independent press scrutinizing its record, policies, and personalities. The national security-related charges used to imprison these journalists are bogus across the board."
Free daily newsletter
- Russian newspaper editor-in-chief Dmitry Muratov receives Golden Pen of Freedom award
- Journalism behind bars: Vice and Al Jazeera advocating for freedom of the press
- Journalism is not a crime: Supporting press freedom by advocating for imprisoned journalists
- IFJ issues safety advice for journalists covering Baku 2015
- 9 publications proudly flying the flag for satire