Private gun shops are now prohibited from selling guns under the measure, which had been announced previously.
Only the police and the military will be exempt from the ban on gun sales, Justice Minister Tareck El Aissami said.
Critics noted that only a small percentage of guns have recently been sold legally to permit holders and said most gun sales have long been illegal and unregulated.
Luis Izquiel, a lawyer who heads a security committee for Venezuela's opposition coalition, said that while there are about 25,000 gun permits legally registered with the authorities, there are many more weapons on the streets. In 2010, Amnesty International estimated there were a total of 10 million firearms in the country.
"Here criminals don't use legal firearms," Izquiel said.
Polls have repeatedly said that Venezuelans view violent crime as the country's top problem.
President Hugo Chavez's government has announced several new anti-crime measures ahead of the country's October presidential election.
Last week, the government imposed another measure prohibiting people from possessing guns in public places such as city squares, parks and restaurants.
In February, the government announced temporary measures outlawing gun possession in public areas as well as halting gun sales. The latest measures have made those changes permanent.
"Now no one is going to be able to get new guns or have new permits," El Aissami said Friday, according to the state-run Venezuelan News Agency.
He said his ministry will have authority over the supply of weapons to police forces.
Venezuela has in recent years had one of the highest homicide rates in Latin America. El Aissami has said that in 2010 the country had 48 murders per 100,000 people.
The Venezuelan Violence Observatory, a watchdog group which tracks crime, says that the murder rate has continued to rise and that last year there were more than 19,000 homicides, a record for the country.