"The amount of the debt has been fixed at $4.6 billion," Kudrin said told journalists in Tripoli.
Moscow had earlier put the debt at about $3.5 billion. Tripoli said in the 1990s that Russia also had an outstanding debt to Libya.
Russia's outgoing president, Vladimir Putin, arrived in Tripoli on Wednesday for a two-day visit at the invitation of the country's leader, Muammar Qaddafi, who referred to the Russian leader's visit as "timely" during their opening conversation.
During the visit, the sides could sign arms contracts worth $3 billion, a Russian leading business daily, Vedomosti, reported earlier this week.
The newspaper said citing a Defense Ministry official that Russia wants to sell 12 of the latest Su-35 Flanker multi-role fighter and Tor-M2E short-range missile systems, and to offer spare parts and maintenance services for Soviet-era military hardware.
