Lloyd's Register (LR) is working on resuming services to verify safety and environmental standards for Iranian shipping companies, the ship classification society said on Monday.
Without verification from such bodies, ships are unable to call at international ports or secure insurance.
"We are now making arrangements to re-establish provision of classification services to existing tonnage and re-opening our Tehran office," LR said in a statement, without providing further details.
LR, one of the world's leading classification societies, suspended operations in 2012 when tougher sanctions were imposed on Iran. On Saturday, world powers lifted measures imposed on the Islamic Republic after a nuclear deal was reached last year.
LR previously provided classification cover for Iran's top tanker company NITC and container and dry bulk group IRISL.
(Reporting by Jonathan Saul; editing by Susan Thomas)