General Oswaldo Hernandez and retired Colonel Jose Delgado were among those sentenced to a minimum of five years, the court said in a statement.

Venezuela's top court rejected a final appeal from the nine defendants who had already seen previous motions dismissed by both a lower court and a court-martial.

They were accused of "preparing in 2014 an insurrectional and destabilizing movement, called operation Jericho, against the government."

The opposition has accused the supreme court of "serving" Maduro's interests.

All nine defendants were arrested between March and May 2014.

According to local press reports, the plan was for certain military detachments to arrest Maduro and other high-ranking government officials in a bid to spark a citizens' revolt to oust the regime.

Maduro, who frequently denounces plots against him, insisted at the start of December that the United States was planning to overthrow him with the help of Colombia's right-wing government and Brazil's far-right president-elect Jair Bolsonaro.

The socialist leader, who has overseen Venezuela's descent into the worst economic crisis of its history, is due to begin a second mandate on January 10 after winning an election earlier this year that was branded a fraud by the US, European Union, opposition groups and the Organization of American States.

According to the Foro Penal charity, there are 278 political prisoners being held in Venezuela, among them 80 military personnel.

Oil-dependent Venezuela has been crippled by a four-year recession that has seen poverty soar as much of the population suffers from shortages of basic necessities such as food and medicines.

Inflation has sky-rocketed with the International Monetary Fund predicting it would pass one million percent this year and 10 million percent next year.

With failing public services such as water, electricity and transport, there has been a mass exodus of Venezuelans.

According to the United Nations, 2.3 million people have left since 2015.