OSLO (Reuters) - The world's shipping fleet could cut carbon emissions by 15 percent in just a few years, and the industry could be carbon neutral in 10 to 15 years aided by new technology, ship classifier Det Norske Veritas (DNV) said.

DNV also said the global shipping fleet had the potential to reduce carbon emissions with 50 percent by 2030.

The current fleet accounts for close to three percent of the world's carbon emissions, comparable to that from the aviation sector, according to DNV, a Norway-based ship classifier and international risk management group.

"If you can achieve a 15 percent reduction (in carbon emissions) from the existing fleet, then it is possible to reach carbon neutral emissions," Tor Svensen, Chief Operating Officer for maritime activities at DNV told a news conference.

His remarks came at the start of a shipping conference in the Norwegian capital this week before a December conference in Copenhagen that will seek a successor to the Kyoto Protocol on fighting climate change.

Svensen said the shipping industry will grow as international trade increases and because ship transport is the most energy efficient way to transport goods long distance.

"We believe a 15 percent reduction in carbon emissions is possible with today's fleet, taking the right measures and taking the right medicine," Svensen said, adding that such a reduction could be reached in two to three years if a determined effort were made.

He said that even bigger reductions could be achieved with new, technologically improved vessels.

"Combining this, we believe that the realistic long-term ambition is carbon neutral growth," he said. "It will take 10 to 15 years to achieve a carbon neutral fleet," Svensen told Reuters on the sidelines of the conference.

DNV said the estimates were based on a snapshot of today's fleet.

Svensen said the costs linked to reducing emissions would be "relatively small" compared to the benefits.

Svensen said about 60 percent of today's ships would still be sailing in 2020, and the real impact on carbon emissions reductions would materialise after 2030 given that most vessels have an average lifetime of about 20-30 years.