Russian President Vladimir Putin will seek to "recharge" ties when he visits India Wednesday for a one-day summit, promising deals on natural gas and new nuclear power units for the energy-starved country.

India -- the world's third largest oil importer behind the United States and China -- has been buying oil mainly from the Middle East but the region's volatility has prompted the government to consider other options.

Russia, which has the world's second-biggest natural gas reserves, is looking to expand energy links with Asian nations to counter sanctions from the US and its allies in the West.

"We have big plans for energy cooperation, it will be item number on the agenda," Russian ambassador Alexander Kadakin told reporters in New Delhi.

India is already a partner in Sakhalin-1, Russia's first large-scale project that works under a production sharing agreement, and Kadakin said Indian companies were "welcome" to explore more of their gas fields.

"We are ready to offer our hydrocarbon to Indian companies if they are interested. India is the only country (to be offered the chance to buy reserves), it testifies to the degree of trust and confidentiality between the two countries."

The Russian announcement comes just days after Moscow was forced to scrap its giant South Stream gas pipeline project amid tensions with Europe over the crisis in Ukraine.

The ambassador also said the two countries had reached an agreement for a unnamed Russian company to build two additional two reactors at Kudankulam, near Chennnai in the southern Indian state of Tamil Nadu.

"Co-operation in peaceful uses of nuclear energy will prominently figure at the summit level talks," Kadakin said.

"The technical agreement on the third and fourth units have been signed, the credit line has also been opened. Negotiations for the fifth and sixth units will also start soon."

The Kudankulam plant deal was first signed in 1988 by then Indian prime minister Rajiv Gandhi and former Soviet leader Mikhail Gorbachev.

However, the collapse of the Soviet Union and Russia's subsequent years of economic mayhem meant that construction did not begin until 2002.

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

Moscow will be looking to invest in at least 22 new nuclear power units, Kadakin said while admitting India's nuclear liability law was something that Russia "didn't like".

The Russian president will also talk diamonds with India's new Prime Minister Narendra Modi.

"India is the largest cutter of diamonds and Russia is the largest producer. Our interests can naturally meet and complement each other," Kadakin said.