"We have repeatedly told... the intervening parties, whether they are the United States or France, that the case does not concern them at all and that they will not help to solve a technical problem if they politicise it," said foreign ministry spokesman Saeed Khatibzadeh.
The Islamic Revolutionary Guard Corps seized the Hankuk Chemi and arrested its multinational crew of 20 near the strategic Strait of Hormuz one week ago.
The move came as Tehran urged Seoul to release billions of dollars of Iranian assets frozen in South Korea as part of US sanctions.
The United States and France have called for Iran to release the ship.
A US State Department spokesperson called the seizure "part of a clear attempt to extort the international community into relieving the pressure of sanctions".
The French foreign ministry said the seizure was "fuelling tensions in the region".
South Korean Deputy Foreign Minister Choi Jong-kun arrived in Tehran on Sunday for a long-planned visit.
On Monday, Choi met with Iran's top diplomat Mohammad Javad Zarif, state news agency IRNA reported.
Zarif told him that "restrictions" on Iranian funds were the "biggest obstacle" to their bilateral relations in the current situation, said IRNA.
The top Iranian diplomat called on the South Korean government to "take the necessary measures" to release frozen funds as soon as possible, it added.
Before their meeting, Choi met with Iran's central bank governor Abdolnasser Hemmati, who called the blocking of Iran's funds in South Korea "unacceptable", according to the bank.
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