Wen made the comments to the visiting First Vice President of Iran, Mohammad Reza Rahimi, in Beijing for a forum of Central Asian states, the official Xinhua news agency reported.
While the United States and European powers call for greater pressure behind demands that Tehran be transparent about its nuclear plans, Wen's comments suggested Beijing remained unwilling to risk its oil and investment ties with Iran by backing such demands.
Wen, quoted by Xinhua, said China was willing "to maintain high-level contacts with Iran, encourage mutual understanding and confidence, promote practical cooperation between the two sides and close coordination in international affairs."
Wen also said: "China is willing to continue playing a constructive role in promoting peaceful resolution of the Iranian nuclear issue."
Russian Prime Minister Vladimir Putin, also in Beijing for the meeting of the Shanghai Cooperation Organization, warned on Wednesday against intimidating Iran and said talk of sanctions over its nuclear program was "premature."
Putin was speaking after U.S. Secretary of State Hillary Clinton failed to secure any specific assurances from Russia on Iran during talks in Moscow.
Wen's comments left little doubt that China wanted to keep at arm's length possible Western demands for stiffer sanctions.
"The Sino-Iran relationship has witnessed rapid development …and cooperation in trade and energy has widened and deepened," Wen told Rahimi, according to Xinhua.
Last month, Iran said it was building a hitherto undisclosed second uranium enrichment facility, drawing warnings from the West that Tehran had to come clean about its activities, which critics say could give it the means to assemble atomic weapons.
Iran says its nuclear activities are for peaceful ends and that it complies with international nuclear rules.
China has voiced concern about the enrichment plant, but urged nations to solve the latest flare-up through negotiations.
Growing energy ties bind China, the world's No. 2 crude oil consumer, and Iran, which has the world's second-largest crude oil reserves but needs investment to develop them. Iranian oil made up nearly 12 percent of China's crude imports last year.
Beijing's distaste for sanctions and appetite for Iran's oil mean it could use its power as a permanent member of the Security Council to soften any proposed resolution on the dispute.
(Reporting by Chris Buckley; Editing by Ron Popeski)
