An oil tanker collided with a US navy ship near the Strait of Hormuz on Sunday, but no one was hurt, the Bahrain-based US Fifth Fleet said.

"The collision between USS Porter (DDG 78) and the Panamanian-flagged bulk oil tanker M/V Otowasan occurred at approximately 100am local time," a statement on the Fifth Fleet's website said.

It said the Porter was a guided-missile destroyer and the oil tanker was Japanese-owned. The navy vessel remained able to operate under its own power after the collision, which was not combat-related, the statement added.

"USS Porter is on a scheduled deployment to the US Fifth Fleet area of responsibility conducting maritime security operations and theater security cooperation efforts," the statement said, adding that the incident was under investigation.

Tensions have risen in the Gulf this year as Iran has threatened to close the Strait to international shipping if its dispute with the United States over its nuclear programme escalates.

Shipping lanes in the Strait of Hormuz, through which 40 per cent of the world's seaborne oil exports pass, have not been affected by the collision, an Oman coast guard official said on Sunday.

"Both vessels are okay and the Strait of Hormuz is not closed and business is as usual there," the official told Reuters, declining to be named under briefing rules. – Reuters