Trade between Iran and China dropped by 18 percent in 2012 to $37 billion after a raft of banking sanctions imposed on the Islamic republic, Iranian newspaper Donya-e Eqtesad reported on Monday.
"Iran-China trade fell to $37 billion in 2012 from $45 billion in 2011," the newspaper quoted Assadollah Asgaroladi, director of the Sino-Iranian Chamber of Commerce, as saying.
"Iranian exporters and importers who are seeking increase in trade volume are facing banking problems."
Asgaroladi has been previously cited in the Iranian media as saying that the Iran-China trade could reach $50 billion in both 2014 and 2015.
Iran is under a series of international sanctions for pursuing its controversial nuclear programme, which world powers believe masks a drive for atomic weapons.
The sanctions have led to a severe economic crisis in the Islamic republic, including choking its banking sector and limiting oil exports -- its main revenue earner.
Asgaroladi said the chamber "has exerted a lot of effort to curb the existing problems" but there has been no breakthrough.
He, however, said that China had invested $600 million in Iran in 2012.
China, the world's second biggest economy, was Iran's top trading partner in 2012, as Western companies withdrew after the United Nations, the United States and the European Union levied sanctions on Tehran.
Energy-starved China remains the biggest buyer of Iranian crude oil despite Tehran accusing Beijing of failing to fulfil its commitment and delaying its contractual obligations in oil and gas projects.