The incident had prompted an angry reaction from Iran, with Iranian forces last month seizing two Greek oil tankers in the Gulf after Tehran warned it would take “punitive action” against Athens.
Iran also appealed the court’s initial decision, a legal source said, declining to be named.
“The action to set aside the decision has been accepted by the court,” the source said. “It will be difficult to overturn this (the decision of the court of appeal).”
It was not immediately clear whether the US or Greek governments would challenge the ruling, which was handed down by the Chalkis region appeals court.
The outcome of the appeal has not yet been made public.
Greece had described Iran’s seizure of the two Greek oil tankers in the Gulf as “piracy”.
The case arose when Greek authorities in April seized the Iranian-flagged Lana, formerly Pegas, with 19 Russian crew members on board, near the coast of the southern island of Euboea due to the European Union sanctions.
The vessel was quickly released due to ownership complications. The United States confiscated part of the Iranian oil cargo held on board in May and transferred it to another vessel, following the first decision of the Greek court.
In a separate case, Greek authorities then seized Lana again, acting on an interim court order over alleged debts to another shipping company, represented by attorney George Kozanidis.
Kozanidis declined to disclose the name of the company he represents, but told Reuters the case was related to unpaid towing services.
(Reporting by Lefteris Papadimas, Renee Maltezou in Athens and Jonathan Saul in London; editing by Richard Pullin)