Hundreds of police officers have lined up in several rows between the protesters and the building of the Cabinet of Ministers, a RIA Novosti correspondent reported.
"This is a symbolic surrounding of the government building. By this, the protesters are expressing their discontent with the illegitimate government," DA Platform activist Vasile Nastase told RIA Novosti.
According to Nastase, tens of thousands people are taking part in the rally.
Earlier in the day, demonstrators adopted a resolution of the protest, stating that Moldova is "a captured state, which must be returned to the people," and that the country's state structures have to become independent.
"The only solution is early parliamentary elections, presidential elections and a referendum no later than July. We demand the establishment of an urgent date of early parliamentary and presidential elections," DA leader Andrei Nastase said.
Chisinau has been swept in rallies since September 2015, when the coalition of opposition forces demanded the resignation of the Moldovan president, the prime minister and the chief prosecutor, as well as prompt action to tackle corruption.