"So far no sanctions against the mentioned countries have been imposed," foreign ministry spokesman Hamid Reza Asefi told the government daily Iran.

Countries reportedly affected by the alleged restrictions include South Korea and Britain -- who backed an International Atomic Energy Agencyresolution last month that paves the way for Iran to be referred to the UN Security Council over its disputed nuclear activities.

Iran had 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).

Although Tehran-based diplomats say they have not been officially informed of trade reprisals, several confirmed that goods were being deliberately held up by Iranian customs as a result of what appeared to be "an unwritten directive".

This appeared to be confirmed by Interior Minister Mostafa Pour-Mohammadi, who was quoted by another paper as saying the government has had "general discussions" on an import ban.

"We see no need to help boom the economy of a country that pays no attention to our national interests," the minister said.

A foreign diplomat told AFP: "There have been problems -- the Iranians are not telling us anything but customs are stopping some of our goods.

"This kind of thing has happened before, although this time it appears to be stricter."

South Korea's deputy foreign minister Lee Kyu-Hyung is due in Tehran in the coming days to discuss the issue, the South Korean embassy said. Last year, the country exported more than 2.4 billion dollars of goods to Iran.

On Thursday, hardline President Mahmoud Ahmadinejad refused to confirm or deny a ban although he did link international relations and trade.

However an MP quoted by the Iran News paper spoke openly of a ban and voiced concern over its effect on Iranian industry which is heavily dependent on imported industrial machinery and parts.

"Our committee will soon investigate the negative effects of the ban on imports from certain countries on Iran's main industries such as auto manufacturing," said Vali Maleki, a member of parliament's industries committee.

He said continuing such a policy would be "economically unfeasible".

The Iran Daily newspaper also reported that the country's position as the Middle East's largest carmaker could be damaged, given that the state-owned firm Saipa could run out of vehicle parts.

One of Iran's most popular cars is the South Korean-designed Kia Pride, which is assembled in Iran by Saipa using 80 percent Iranian-made parts. The remaining parts come from South Korea.

Why Iran appears to be mainly picking on South Korea and Britain is a mystery given that some 20 other countries also backed the IAEA resolution.

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