Mahmoud Ahmadinejad, the Iranian president, is due to sign trade agreements with Zimbabwe during a visit to the country.
At a trade fair in Bulawayo, the second largest city in Zimbabwe, on Friday, Ahmadinejad said that the level of trade between the two nations was not at full capacity and should improve.
Robert Mugabe, the Zimbabwean president, gave his support to Iran's nuclear programme on Thursday when Ahmadinejad arrived in the capital Harare for a two-day visit.
At a banquet Mugabe said that Western nations were acting against both Iran and Zimbabwe for asserting their independence.
'Vilified and punished'
"Because of the principled positions we have taken at both the domestic and international level, Zimbabwe and Iran have been unjustly vilified and punished by Western countries," Mugabe said.
"Be also assured, comrade president, of Zimbabwe's continuous support of Iran's just cause on the nuclear issue," he said.
The US is pushing for new UN sanctions against Iran over its refusal to cease uranium enrichment. The US believes that Iran's nuclear programme is intended to create nuclear weapons, while Ahmadinejad's government has said it is for peaceful power.
Zimbabwean state media quoted Ahmadinejad as having said that the UN security council was being used by western powers to prevent Iran from achieving nuclear power.
"Unfortunately, the United Nations Security Council, which is supposed to serve the whole world, has been used by the powerful to increase pressure on our countries," he said.
Mugabe, leader of the Zanu-PF party, is blamed by some to have led Zimbabwe into ruin and was pressurised into a power-sharing agreement with his rival, Morgan Tsvangarai, by international powers in 2008.
'Colossal political scandal'
Tsvangarai, now Zimbabwe's prime minister, had dropped out of a second round run-off vote in presidential polls after election violence, leading Mugabe to take the presidency unchallenged.
Tense relations between Mugabe and Tsvangirai's Movement for Democratic Change (MDC) have been excentuated by the invitation to Iran's president to visit. Tsvangirai has called it a "colossal political scandal" and he and his party boycotted a welcoming party held for Ahmadinejad.
"Ahmadinejad's visit is not only an insult to the people of Zimbabwe, but an affront to democracy and to the oppressed people of Iran," the MDC said in a statement.
Mahjoob Zweiri, an expert in Middle East politics and Iran at Qatar University, told Al Jazeera: "Theses two states try to show that economic cooperation can be achieved even without the support of the European nations.
"They insist of building a bridge without western nations.
"It opens more gates to their products and their investors, and they try to circumvent economic problems because of western sanctions."