EU rules limiting the amount of sulphur in shipping fuel come into force on New Year's Day.
The Sulphur Directive limits the maximum amount of sulphur in fuel to 0.1 per cent from 1 January 2015, as part of efforts to reduce greenhouse gas emissions.
Shipping companies have warned the directive will push up costs by a third because low-sulphur fuel is more expensive.
Firms have the options of switching fuels, changing to liquefied natural gas or installing “scrubbers” that remove sulphur from exhaust gases, all of which have cost implications.
The EU has said shipping accounts for around 4 per cent of Europe’s greenhouse gas emissions, and without action these emissions are predicted to more than double by 2050.