China said Wednesday it opposed the United States "spreading false information" after US Secretary of State Antony Blinken said Beijing's support for Russia's defence industry "has to stop".

China is providing critical support that enables "Russia to keep that defence industrial base going, to keep the war machine going, to keep the (Ukraine) war going," Blinken told a joint news conference in Washington with NATO Secretary General Jens Stoltenberg on Tuesday.

China presents itself as a neutral party in the Ukraine war and says it is not sending lethal assistance to either side, unlike the United States and other Western nations.

"We resolutely oppose the United States spreading false information without any evidence and passing the blame onto China," foreign ministry spokesman Lin Jian said at a regular news briefing.

"On the question of the Ukraine crisis, China has never added fuel to the fire or sought to profit from the situation, and has always been dedicated to peace talks," he said.

"China does not provide weaponry to any party in the war, strictly controls exports of joint civil-military items, and has won high plaudits from the international community," Lin said.

China and Russia's strategic partnership has only grown closer since the invasion of Ukraine, but Beijing has rebuffed Western claims that it is aiding Moscow's war effort.

It has however offered a critical lifeline to Russia's isolated economy, with trade booming since the conflict began.

Stoltenberg said during his briefing with Blinken that China should face "consequences" if it keeps backing Russia.

"China cannot have it both ways. They cannot continue to have normal trade relationships with countries in Europe and at the same time fuel the biggest war we have seen in Europe since the Second World War," he said.

G7 foreign ministers expressed "strong concern" last week about transfers of dual-use materials and weapons components from Chinese businesses to Russia being used by Moscow for its military expansion.

China steered clear of a weekend summit in Switzerland promoted by Ukrainian President Volodymyr Zelensky that reaffirmed Kyiv's demands for Russia to leave Ukrainian territory for any peace to be won.