China said Wednesday that "a lot of work" would need to be done before a planned peace conference on the Ukraine war could take place in Switzerland, but did not say whether it would attend the meeting.

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

And while China says it is a neutral party in the Ukraine conflict and has even sought to play a mediator role, it has been criticised for refusing to condemn Moscow's offensive.

With the war well into its third year, the Swiss government last week announced that it would host a high-level peace conference for Ukraine in mid-June, but that Russia would not attend.

Following talks with President Xi Jinping in Beijing Tuesday, German Chancellor Olaf Scholz said that he and the Chinese leader had agreed to "coordinate intensively and positively" on promoting that conference.

Ukrainian President Volodymyr Zelensky welcomed the statement, saying that China could help deliver a "just peace" for his country.

But Moscow has said that holding the peace conference makes "no sense" unless Russia takes part.

Russia's foreign ministry spokeswoman Maria Zakharova said last week that any action on Ukraine that "ignores Russia's position" was "detached from reality" and had "no perspective".

The Kremlin has repeatedly said it will not participate in any negotiations unless Kyiv accepts Russia's annexation of the roughly 20 percent of Ukraine's territory it currently occupies.

China has not officially confirmed it would attend the planned meeting in Switzerland, saying Xi supported a conference "recognised by Russia and Ukraine" and that "there is still a lot of work to be done" before it takes place.

Xi "supports the convening of an international peace conference in due course... with equal participation by all parties," foreign ministry spokesperson Lin Jian said.

"China believes that any conflict must ultimately be resolved through diplomatic channels and political negotiations," Lin added.

"The only way out of the Ukraine crisis is at the negotiation table," he said.

Scholz also said on Tuesday he had urged Xi to use his leverage with Russia to press it to end the "senseless" war in Ukraine and withdraw its troops.

"China's word carries weight in Russia," he said.

State broadcaster CCTV on Tuesday also said Xi had laid out what it described as "four principles to prevent the Ukraine crisis from spiralling out of control and to restore peace".

Nations must focus on "the upholding of peace and stability and refrain from seeking selfish gains", Xi said, as well as "cool down the situation and not add fuel to the fire".

"We need to create conditions for the restoration of peace and refrain from further exacerbating tensions," Xi said, while aiming to "reduce the negative impact on the world economy".

The "four principles" echoed a Beijing paper last year that called for a "political settlement" to the conflict, which Western countries said could enable Russia to hold much of the territory it has seized in Ukraine.