Several reports have suggested that Iran has imposed a ban on products from countries, including Britain and South Korea, who backed an International Atomic Energy Agency (IAEA) resolution last month that paves the way for Iran to be referred to the UN Security Council over its disputed nuclear activities.

"Our government is trying to verify the reported move by the Iranian government through diplomatic channels," South Korea's Foreign Minister Ban Ki-Moon said Wednesday at a press briefing in Seoul.

Hardline President Mahmoud Ahmadinejad would only assert that trade and international relations were linked.

"The economic and political policies of Iran must be connected. Political relations should not go in one direction and economic relations go in another," he was quoted as saying by the official news agency IRNA.

But when asked to comment on South Korea's concerns, Ahmadinejad simply replied that he was unaware of the reports.

Earlier this week the intelligence ministry had denied sanctions were being imposed, but Iran's commerce ministry and foreign ministry have declined to comment on the reported import blacklist.

Iran last month vowed to punish its trade partners if they voted for the resolution, which chastised Iran for being in "non-compliance" with the nuclear Non-Proliferation Treaty (NPT) and cemented concerns the country is using an atomic energy drive as a cover for weapons development.

An Iranian importer of South Korean electrical goods, who asked not to be named, said he had not experienced any problems.

And foreign diplomats from countries that could be affected by such a blacklist said they had not been informed of any specific sanctions, but added that customs problems have occurred in the past during moments of tension with Iran.

"It could just be a case of customs problems for products from certain countries. This is normal," a foreign diplomat said.