Chavez has called the new TV channel "socialist television".
"I believe that the closing-down of the television station is very justified"
Medishagh, Nouakshott, Mauritania
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The action against the network sparked protests over the weekend.
Using water cannons, police dispersed thousands of stone-throwing protesters outside Venezuela's telecom authority, the body which ordered RCTV off air.
Chavez's political opponents champion RCTV as an opposition voice, and criticise his refusal to renew its broadcast licence.
Venezuela's supreme court ruled that RCTV must temporarily leave its equipment and broadcast infrastructure in military hands to ensure that TVes can provide quality service.
Marcel Granier, the president of RCTV, called the decision "an unconstitutional seizure of our equipment".
Station managers have asked its 3,000 employees to remain in the studios overnight and to be ready for work on Monday - possibly to hinder the handover.
RCTV owners "have a plan to sabotage the new channel's signal," Chavez said on Saturday.
Meanwhile, Chavez supporters began a huge, night-to-dawn public party outside RCTV studios to celebrate the birth of the new station.
About 70 to 80 per cent of Venezuelans oppose the restrictions, according to recent polls.
Chavez announced the decision not to renew the licence soon after he was re-elected in 2006.
During the campaign, RCTV openly called for the president's defeat, and Chavez never forgave the network for calling the coup against him in April 2002.
RCTV, which airs popular programmes and variety shows, has one of the largest audiences in Venezuela. It is also one of the few stations with national broadcast capabilities.
As of Monday, the government will control two of the four nationwide broadcasters in Venezuela, one of them state-owned VTV.
However, the government renewed the broadcast licence for Venevision which expired on Friday – the channel was RCTV's main competitor.
Venevision is owned by Gustavo Cisneros, a billionaire who dropped his opposition to Chavez in 2004.
El Nacional daily in a front-page editorial said RCTV's shutdown marked "the end of pluralism" in Venezuela and the government's growing "information monopoly".
Chavez and his ministers deflected criticism, saying other media could still carry the RCTV signal.
However, Granier said, "The government is pressuring cable and satellite companies not to carry us."