The company said the amount of oil released was believed to be less than one barrel.
However, it stated that as a precautionary measure, loading was immediately suspended and the loading line was depressurised, following which the oil sheen was said to have dissipated quickly.
While investigations were reportedly underway to determine the source of the oil, the company said that bad weather was delaying crew and equipment from inspecting the loading line and being able to undertake any necessary repairs.
A diving support vessel capable of operating in harsh weather conditions is currently being mobilised to site, along with all required support equipment.
It is expected to arrive at the terminal around 6 August.
Oil Search stated that the impact on production had, to date, been minimal.
However, it said that storage facilities were approaching full capacity and warned it may need to reduce output if the weather did not improve.
“If the weather does not improve to allow the company to undertake the required inspections and implement any required repairs using the equipment already on site, production will be curtailed progressively over the next week,” Oil Search stated in an Australian Securities Exchange release.
Oil Search said it had notified PNG’s Department of Petroleum and Energy of the incident, as well as other relevant authorities in the country.