"The deportation order was revoked because Sean is married to an Ecuadorean citizen and his visa is legal," O'Hearn's attorney, Gina Soli, told reporters.

Correa, a leftist who has vowed to protect the environment, accused O'Hearn of violating the country's sovereignty by participating in the police raid earlier this week.

O'Hearn denies any wrongdoing and says he was only an observer in the raid that seized two tonnes of shark fins. US-based Sea Shepherd had previously signed a deal with the Ecuadorean police to protect marine wildlife.

Correa has been under fire from environmentalists since he issued a decree in July that allows thousands of fishermen to sell the fins of sharks that are caught accidentally.

"Sea Shepherd wishes to thank President Correa for this action and urges him to rescind the presidential decree that allows for the trade in shark fins," Sea Shepherd said in a statement after O'Hearn was freed. "Sea Shepherd is preparing a detailed report on the incident and the overall situation within the next few days."