The opposition leader is among 25 suspects said to have been seeking to seize parliament.
Opposition leader Andrija Mandic is among 25 suspects said to have been seeking to seize parliament and assassinate the country's then prime minister during an election last year.
Parliament lifted the immunity of Mandic and another pro-Russian MP last month so they could potentially face charges in a case with echoes of Moscow's alleged interference in the US election.
Montenegro hopes to soon become a NATO member, a move considered by Russia to be a "provocation" as it would reinforce the pro-Western military alliance's presence in the Balkans.
In an interview with AFP, Mandic dismissed the allegations of a coup -- police arrested a group of Serbian nationals on the eve of the vote -- as a "staged political process" to discredit him and his party.
"Our political opponents want to see their opponents in the dock," he said, laughing off attempts to link him with "third-rate spies... so good that they were incapable of doing anything" at the election.
"Without shame, the prosecutor follows the path indicated by the chief of the regime," Mandic said, referring to former prime minister Milo Djukanovic.
Djukanovic, a veteran politician who has led the country of 620,000 people towards integration into European Union and NATO, quit the government after the October 16 election, despite his party's victory.
However his opponents still consider him the real leader of the Balkan nation.
Montenegrin prosecutors have said that "Russian state bodies were involved" in the coup plot, saying the Serbs, several of whom have been convicted, were hired to carry it out. Moscow denies the allegations.
Mandic, who could face eight years in jail if charged and ultimately convicted, and Milan Knezevic, both of the opposition Democratic Front (DF), are accused of knowing about the coup.
A parliamentary motion before they were stripped of their immunity accused them of "creating a criminal organisation... and preparing an attempt on the constitutional order and security of Montenegro."
But Mandic told AFP he was "a serious politician," leader of a "conservative party that defends tradition" and "has nothing to do with terrorism or any armed action."
Having previously said clashes could erupt if he is charged, Mandic would not say if he would urge supporters to take to the streets if parliament ratifies the country's accession to NATO, which is expected in spring.
Protests against the military alliance in 2015 turned violent. Mandic and the DF have demanded a referendum, but the ruling coalition has refused.
"Montenegro is in a deep political and economic crisis. This is a deeply divided society, on the verge of conflict," Mandic said.
A way out would be general elections in "early 2018," under the supervision of the EU but also "two great powers that have influence in the region, the United States and Russia," he added.
Montenegro's accession would boost NATO's presence in the volatile region as Albania, Croatia and Greece are already members.