"Internet users can open only local sites and local mail. For overseas sites and mail, the internet has been down since 8:00 am Thursday," said an official from the state-owned telecoms provider Myanmar Teleport.
"It happened because the gateway is down. We don't know yet when it will be back up," the official told AFP wthout elaborating.
Burma dissident websites and blogs have been particularly active in the lead-up to Mr Gambari's visit, condemning the junta for its suppression of demonstrators and urging the international community to ramp up pressure on the regime.
"Since the world witnessed the brutality of the military, the reputation of the junta has suffered an irreparable damage, especially at home, and also abroad," said a commentary posted Friday on the anti-junta website Mizzima News.
"Even though the soldiers are still present the people of Burma do not run away to other countries ... They are outgunned for the moment but every indication is pointing to their determination to remain defiant," it said.
Dissident websites are also frequently the quickest means of relaying information from within the isolated country.
They were a key source of news on a march on Wednesday by Buddhist monks in central Burma, the first such demonstration since the September crackdown.
"We have lost our internet connection completely and have to rely on the fax machine to make contact with the outside world," said one tour company operator who did not want to be named.
Internet cafe staff also confirmed that their web connections had been drastically reduced.
"The internet has been down since (Thursday). We have only limited access and have to ask customers to come back again and again," one cafe worker said.
At the height of the unrest in September, Burma's internet connections were cut as the military regime tried to stop the flow of news and images of its suppression of mass protests.
Paris-based media rights group Reporters Without Borders at the time condemned Burma as a "paradise for censors" and listed the country as one of the world's most restrictive for press freedoms.
In early October following the interruption of internet services, UN telecommunications agency chief Hamadoun Toure said in Geneva that no government had the right to cut their citizens off from the internet.