Ma also discussed promotion of the Electronic World Trading Platform (eWTP).
The two countries account for more than 25% of the world's crude oil production.
Veteran Labour MP has served as head of the influential group since 2007.
The prime minister is said to be planning tougher entry rules for migrants in lieu of a points system.
President Xi had face-to-face with PM in China over delayed multi-billion pound project
Theresa May will look to imitate David Cameron's close relationship with Xi Jinping.
Boris Johnson insists Britain 'operates one of the most robust arms export control regimes in the world'.
Futures rose by 1.5% after two of the world's leading producers agree to try to stabilise global supply.
The UK prime minister says such a deal may not be the 'silver bullet' to curb EU migrant levels.
Japan's government's says the UK's exit from the EU will 'a major disturbance to the world economy'.
Security chiefs warn Britons in Hangzhou they may be targetted by Chinese spies.
Obama says US will finish trade deals with the EU and Asia-Pacific nations first.
Theresa May faces renewed calls for Britain to ratify the COP21 accord.
May to have one-to-one meetings with Barack Obama, Vladimir Putin, Narendra Modi and Xi Jinping.
The boys organised the visit to the Russian capital 'entirely on their own initiative'.
Beijing unlikely to accept a watered-down agreement as Number 10 reviews UK nuclear options.
Local hotels claim the police warned them against allowing guests from these particular nations.
As a lengthy negotiating process looms ahead, the chancellor points to 'uncertainty' over Brexit outcome.
UK chancellor says negotiating clarity on both sides would reduce uncertainty.
Ministers did not divulge their plans on how to boost growth.
The agreement between UK, France, Germany, Italy and Spain is in response to the Panama Papers leak.
Top Conservative says it is the 'very worse time' for Britain to break away from Brussels.