China condemned on Tuesday what it called "groundless accusations" by the United States that Beijing is supporting Russia's war in Ukraine.

"The United States has unveiled a large-scale aid bill for Ukraine while also making groundless accusations against normal trade between China and Russia," foreign ministry spokesperson Wang Wenbin said.

"This kind of approach is extremely hypocritical and utterly irresponsible, and China is firmly opposed to it," he said.

China and Russia have ramped up economic cooperation and diplomatic contacts in recent years and their strategic partnership has only grown closer since the invasion of Ukraine.

China says it is a neutral party in the Ukraine conflict but has been criticised for refusing to condemn Moscow for its offensive.

And ahead of a planned visit to Beijing by top diplomat Antony Blinken this week, the United States had accused China of helping Russia, in the throes of the Ukraine war, carry out its biggest militarisation since Soviet times.

Blinken said Friday that China was indirectly fuelling the Ukraine war with the supply of components to Russia that it uses for its military expansion.

"When it comes to Russia's defence industrial base, the primary contributor in this moment to that is China," he told reporters after a G7 ministers meeting in Capri, adding that this is "allowing Russia to continue the aggression against Ukraine".

US officials say China has stopped short of direct military assistance but has provided dual-use supplies that have let Russia regroup in the face of a long delay in US aid to Ukraine due to inaction in the House of Representatives, led by former president Donald Trump's Republican Party.

China has long denied claims it is aiding Russia's war in Ukraine and insisted it won't accept "criticism or pressure" over its ties with Russia.

"On the Ukraine issue, China has always maintained an objective and just position, advocated actively for peace talks and pushed for a political resolution," Wang said Tuesday.

"China consistently implements regulations on the export of dual-use items," he said.

"China is neither a creator nor party to the Ukraine crisis and has never thrown oil on the flames," Wang said.

"We will not accept others passing the buck or shifting blame onto us."