Indian Prime Minister Manmohan Singh meets Russian President Vladimir Putin on Monday hoping to clinch a delayed nuclear power plant agreement and expand Soviet-era military ties.

Singh is using one of his last major foreign trips as prime minister before 2014 general elections to seek resolutions to lingering issues with two of India's most important regional partners.

The 81-year-old prime minister will leave Russia for China on Tuesday in a bid to forge closer economic relations and ink a pact to ease tension along their disputed border in a remote Himalayan region.

"The scope of our relationship with Russia is unique, encompassing strong and growing cooperation in areas such as defence, nuclear energy, science and technology, hydrocarbons, trade and investment," Singh said in a statement before leaving India.

Singh's trip to Moscow was preceded by gruelling behind-the-scenes negotiations on the next phase of a Russian-built nuclear power plant project on India's south coast.

A deal for the Kudankulam nuclear power plant was first signed in 1988. But the collapse of the Soviet Union and Russia's subsequent years of uncertainty meant that construction did not begin until 2002.

Work has been nearly completed on the first two units despite local protests that halted operations for six months in 2011-2012.

India now hopes to strike deals for an additional two reactors at the same plant as it looks to meet surging electricity demand.

But the 2010 Fukushima nuclear power plant accident prompted India to adopt a strict new safety liability law that Russia believes should not be applied to this project since it was conceived in Soviet times.

Negotiations about how the dispute can be skirted in time for Singh's meeting with Putin have gone down to the wire.

Singh said days before flying to Moscow he was confident that contracts on the third and fourth reactors at the Kudankulam plant "would be finalised shortly."

But Moscow's Kommersant daily cited Indian sources as saying that "an agreement on the construction of the third and fourth reactors at the Kudankulam nuclear power plant will not be signed during this summit."

A Kremlin statement issued prior to Singh's visit made no direct mention of the Kudankulam negotiations while noting that military ties "remain one of the priorities in the Russo-Indian partnership."

Moscow news reports said the sides were also discussing an agreement on Russia retrofitting four existing Indian diesel-electric submarines and leasing several more.

A Russian military source told the state-run RIA Novosti news agency that New Delhi was also interested in financing the construction of a nuclear-powered submarine that could be delivered to India in the years to come.