President Xi Jinping will meet his Russian counterpart Vladimir Putin for the second time in six months and the two are likely to discuss cooperation in large-scale projects, a senior Chinese diplomat said.

"Xi is scheduled to meet with Russian President Vladimir Putin and their talks may focus on cooperating on ‘mega projects' between China and Russia and on further strategic coordination at international and regional levels," Chinese Ambassador to Russia Li Hui said in an interview before Xi's arrival in St. Petersburg on Wednesday for the G20 summit.

A policewoman patrols an area of the sea port in St Petersburg on Tuesday. Russia's second city will host the G20 summit this week. President Xi Jinping will meet his Russian counterpart Vladimir Putin during the summit.Alexander Demianchuk / reuters

The two are expected to exchange views on proposed US strikes on Syria, following Washington's claim that the Syrian government used chemical weapons on its own people. Putin has previously voiced opposition to the US stance and China has been urging the US to present evidence of chemical attacks.

Li said Xi's meeting with Putin, the second in six months, strongly illustrates the strategic importance of the China-Russia relationship.

He used a Chinese saying to describe the two meetings: "Sowing in spring and harvesting in autumn".

"Presidents Xi and Putin reached parcels of shared understanding during Xi's first state visit to Russia in early spring. Now it is time for the two leaders to summarize the progress made during that previous visit," Li said.

Russia was the first country Xi visited shortly after being elected president at the annual National People's Congress in March.

"China and Russia recognize each other as their most important strategic partners, and they have their soundest relations in history so far," Li said.

He said the two leaders will be determined to expand on their political partnership into new areas to achieve common development and prosperity.

Li said he expected they would launch more big projects, but did not give details.

China and Russia have already initiated large-scale projects in oil and natural gas transportation with a pipeline from Russia to China.

This summer, both countries were struck by devastating floods, but it is still not clear whether they will undertake mega projects for flood prevention.

"The two have huge potential to tap into economic cooperation, built on their close political partnership, and China is willing to expand investment in Russia, especially in mega projects."

Li said mega projects may help realize the goal of expanding bilateral trade volume to $100 billion in 2015 and $200 billion in 2020.

China's investment in Russia in the first quarter of this year surged to $2.23 billion from $740 million in all of 2012, according to Russian statistics.