Propaganda and Education Department head Ho Quang Loi said hundreds of hired "Internet polemicists" are used in the fight against "online hostile forces," a report by the BBC said.
The department has more than 400 online accounts and 20 microblogs, Ho reportedly said.
The bloggers -- "public opinion shapers" -- take part in online discussions, attacking other bloggers critical of the regime, its policies and who call for greater democracy.
Ho's admission comes after a court in Vinh in Nghe An province, northern Vietnam, sentenced 14 activists, many of them bloggers, to up to 13 years in jail followed by several years of house arrest.
Their convictions relied on loosely worded national security laws -- in this instance article 79 of the penal code, which vaguely prohibits activities aimed at overthrowing the government.
Human Rights Watch condemned the sentences and called for the activists to be released.
"Instead of imprisoning critics, the Vietnamese government should be honoring them for their efforts to address the myriad problems facing the country that the government itself has also identified," Human Rights Watch said.
The U.S. Embassy in Hanoi also condemned the sentences saying they are "part of a disturbing human rights trend in Vietnam."
The defendants were arrested between August and December 2011 and held until trial last week.
The trial was notable for being one the largest group trials in the country and possibly was an example that the government intends to come down harder on bloggers and other Internet users.
Ho claimed his department's bloggers have helped stop negative rumors about the government and blocked online calls for anti-government illegal protests in Hanoi streets.
The BBC said on one of its Vietnamese Facebook walls linked to a story about a clamp down on dissent a pro-government blogger asked why the United States "gave themselves the right to criticize other nations on human rights" and it "should have a look at their own record."
Another post criticized pro-democracy activists saying they "are becoming more and more ridiculous" and "have shown their true color as political opportunists."
A report by the Committee to Protect Journalists said Vietnam's crackdown on independent bloggers hit a new low this month with reports of state officials physically harassing a detained online reporter.
In her account posted to the Danlambao collective blog and reported by CPJ Southeast Asia Representative Shawn W. Crispin, Nguyen Hoang Vi said police beat and stripped her while she was in custody in Ho Chi Minh City, formerly Saigon.
She also said police ordered state nurses to conduct a vaginal search because they suspected she was hiding "illegal exhibits" and videotaped other officers as they violently removed her clothes.
After initially refusing, the nurses conducted the search.
In another CPJ report published in September, Geoffrey Cain, a researcher on Vietnam's censorship, said press freedoms have been worsening since 2006 when two local reporters broke a story on a scandal at the Ministry of Transport, known as PMU-18.
The journalists were given prison terms for "abusing democratic freedoms," Cain said.
But the Communist Party has allowed some reporting on corruption at local level.
Cain said the party's practice -- known as "deliberately incomplete censorship" -- disciplines and humiliates provincial civil servants and police officials outside the party's central reach.
Local journalists also said increased competition among factions inside the Communist Party has made decision-making over media policies less predictable.
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