LAUSANNE (Reuters) - Any lifting of sanctions on Russian energy is likely to be slow and patchy, meaning a return of its oil and gas to markets beyond Asia would likely be modest in the short term, the bosses of the world's biggest trading houses said on Tuesday.

The heads of Vitol, Mercuria, Trafigura and Gunvor, which used to dominate Russian oil trade before the 2022 invasion of Ukraine, told the FT Commodities Global Summit in Switzerland they would be extremely cautious about trading Russian volumes.

But none of them ruled out touching Russian energy, highlighting a dramatic change of approach being considered by the industry after U.S. President Donald Trump upended U.S. policies towards both Russia and Ukraine.

"We do think it's going to be a year or two," Vitol CEO Russell Hardy said of Europe's easing its sanctions regime.

"You're probably going to see some changes to pipeline flows, some countries may choose to import oil and others choose not to," he added.

Trafigura CEO Richard Holtum said the U.S. could be the first to lift sanctions, while EU and UK restrictions would stay in place for longer.

"You would need to see a wholesale winding back of all the sanctions before it's something that could even be considered."

The White House has already begun to draw up plans to give Russia sanctions relief as part of Trump's effort to end the war in Ukraine, while European officials said recently they would seek to avoid Russian oil even if sanctions were eased.

Gunvor CEO Torbjorn Tornqvist said Russia may not wish to return to the pre-war status quo of signing long-term contracts with traders and oil firms to handle shipping and marketing, given the efforts it made since 2022 to build its own commodity trading system.

"They have their own ways now, use their own controlled system to bring oil to the markets."

Tornqvist added that Russia would likely prioritise regaining access to Western banking and payment systems to facilitate trade in sanctions negotiations.

"If sanctions are lifted we would absolutely consider if we can bring value," said Mercuria CEO Marco Dunand.