The Maritime and Port Authority of Singapore (MPA) has requested the Iranian maritime authorities to investigate the shooting at a Singapore flag tanker last week by Iranian naval vessels, reports London's Tanker Operator.

The 2009-built Norwegian managed MR Alpine Eternity had collided with an Iranian oil drilling platform in March, which resulted in a request from Iran to neighbouring Gulf states to seize the ship and hand it over.

MPA confirmed that it had requested Iran to prevent future incidents, as the freedom of navigation and free flow of commerce are of critical importance to Singapore and other countries.

"Such interference with navigational rights is a serious violation of international law," MPA said in a statement.