Narendra Modi and Putin will meet on the third leg of the Indian leader's four-nation tour of Europe with the pair looking to bolster declining trade between the once key partners.

Modi is the guest of honour at this year's three-day Saint Petersburg Economic Forum - Russia's answer to Davos - that Putin wants to use to push the idea that Russia has turned the page on a brutal recession caused by low oil prices and sanctions over Ukraine.

Speaking to journalists as the showcase kicked off, the combative Kremlin strongman insisted that measures against Moscow, including economic sanctions, had ended up having "zero effect".

Putin said he hoped "Russophobia" in the West would "not last for too long, not forever, if only because the understanding has to come that it is counterproductive and harms everyone."

For the Kremlin, India represents the sort of major emerging market it wants to do more business with as it looks to insulate itself against geopolitical shocks with the unpredictable Donald Trump in the White House.

"It is very clear that there will be a very strong statement that Russia is looking to diversify its political relations, is not looking to have one best friend," analyst Chris Weafer from Macro Advisory told AFP.

"Rather than praising China or being critical of Europe, they will try to say 'We are going to be diversified, we are going to be open'."

Boosting India trade

Russia and India enjoyed a decades-long alliance forged during the Cold War, when the Soviet Union was New Delhi's largest trading partner, diplomatic ally and main arms supplier, providing everything from tanks to aircraft.

But the relationship became unmoored following the collapse of the USSR, as India underwent an economic transformation and increasingly sought to build trade ties with Western nations.

That process has accelerated in recent years as New Delhi has orbited closer to Washington, and Russia has fostered relationships with India's chief regional rivals Pakistan and China.

Modi and Putin are expected to oversee a number of deals and discuss a framework agreement for Moscow to supply more reactors to a nuclear plant in southern India as the country seeks to reduce its reliance on highly polluting coal.

A revival of two-way trade, which slumped to below $8 billion in 2015 despite an ambitious bilateral target of $30 billion by 2030, will be a key priority during Modi's visit, after he made visits to Spain and Germany and ahead of a trip to France.

While India will occupy pole position at the forum, other visiting international leaders include UN Secretary General Antonio Guterres and Austrian Chancellor Christian Kern.

Bosses from Chevron, Exxon and Boeing are among 144 US firms at the event, the best attendance in years after Washington previously warned business leaders against attending due to political tensions.

While Russia is talking up its recovery, the situation remains precarious and attention will also focus on talk of much-needed reforms to modernise its creaking economy.

But analysts warned that with Putin likely to bid for another term as president in elections next year there are unlikely to be any radical changes.

"Structural changes are necessary but to put them into action is not easy," Russian Finance Minister Anton Siluanov said