Iran’s says it expects an oil cargo earlier seized by Greece to be returned in full following a Greek court overruling the original decision to confiscate.

The Greek court overturned an earlier court ruling that had allowed the confiscation in May by the United States of part of a cargo of Iranian oil on an Iranian-flagged tanker off the Greek coast, Reuters reported on Wednesday.

The court ruling has not yet been made public, but Iranian officials and state media confirmed the news on Thursday.

The United States has imposed oil export sanction on Iran since 2018 when Washington withdrew from the Obama-era nuclear agreement with Tehran known as the JCPOA.

"Following intensive follow-up, the Greek Court of Appeals will overturn the initial court ruling on the confiscation of Iranian oil and, by God's grace, the entire oil shipment will be returned," Iran's ambassador Ahmad Naderi said on the embassy's Twitter account.

The confiscation of the cargo prompted an angry response from Iran, with Iranian forces last month seizing two Greek tankers in the Gulf after Tehran warned it would take "punitive action" against Athens.

"The issue will remain on the agenda of intensive consultations between the two countries until the full implementation of the ruling is certain," Naderi added.