The International Maritime Organization (IMO) has said it will not force existing ships to fit ballast water treatment systems until the first statutory dry docking survey after 2019.

Under the original version of the convention, owners of existing ships would have to fit the equipment at the first special survey after September this year.

The deal, rubber-stamped by the IMO today, in effect gives owners a two-year reprieve before they will have to comply with the convention, with some owners able to avoid fitting equipment until 2024.