Iran's hardline judiciary arrested the son of a former minister of culture on Nov. 18 on suspicion of involvement in a controversial oil contract, according to the semi-official Fars news agency.

Four years ago, Iran's government tried to bypass the international sanctions on its oil and gas sector and buy an oil rig from a European company. Even though Tehran ended up paying out $87 million, the rig was never delivered to Iran.

Fars, quoting an unnamed source, said: "Mohammad Mohajerani's arrest was related to his role in the missing oil rig case."

Mohammad Mohajerani denied all allegations against him in a statement published on ILNA news agency in August, saying all his activities had been "in the framework of the Islamic Republic economic regulations."

A few Iranian officials have been arrested in Iran in the last few months as part of a judicial investigation into possible corruption related to the deal.

The 'missing rig' became a focus for media seeking to illustrate the complexity and cost of avoiding sanctions.

The U.S.-led penalties will be lifted early next year following an international agreement on Tehran's disputed nuclear programme in July, clearing the way for foreign oil firms to return to Iran.