He said members of the Democratic Unity Roundtable (Mud) coalition had been “caught red-handed.”
Speaking from Vargas state, where he was meeting candidates of his United Socialist Party (PSUV) in this month’s regional elections, Mr Maduro said: “We have our hands on part of this group.”
Electrical Energy Minister Luis Motta said on Saturday that at least 50 suspects had been arrested over the past two weeks for involvement in a plan to sabotage the national grid.
He said 38 others had been killed while trying to steal high-tension electricity cables, while others got away with 19,000 metres of the material.
A spate of similar incidents occurred last year.
Mr Motta said the conspiracy may have been timed to coincide with the October 15 elections, while Vice-President Tareck El Aissami indicated that it had been aimed at hindering the relaunch of the Paraguana Special Economic Zone project intended to bring development to the country.
However, Mr Maduro said tapwater and household gas supplies had also been targeted.
He argued that the plot showed the Mud’s desperation — less than three months after the overwhelming 8.1 millon turnout for elections to the National Constituent Assembly, which the opposition boycotted.
“They are desperate,” the president said. “There are leaders from the highest levels of the opposition involved in attacking the water, the electric system and the gas.”
Mr Maduro called on the people to defend the peace of the nation, which he predicted would be restored by the new assembly.
He also instructed Mr Aissami, whos chairs the national counterterrorism command, to probe the source of funding for the Mud election campaign, which has spent heavily on political broadcasts.
Meanwhile, Communist Party of Venezuela (PCV) political bureau member Pedro Eusse laid out a “rosary of demands” in a letter to the PSUV.
The letter said that the PCV’s alliance with the ruling party was to “ensure that state governorships are not won by the fascist right” which would use them as part of its “destabilising, violent and anti-democratic plan.”
He urged the government to halt “speculation and usury” in the bolivar currency and commodities, which has led to hyperinflation.
He said the PCV was concerned that some agreements with the PSUV had not been honoured, adding: “This anti-imperialist alliance must be fortified.”