Danish shipping giant AP Moller-Maersk is backing proposals for a market-based carbon tax to bridge the gap between fossil fuels and greener alternatives.

Chief executive Soren Skou has proposed a carbon tax on ship fuel of at least $450 per tonne fuel at the present oil price.

The carbon component would amount to at least $150 per tonne of CO2, but the higher figure is deemed necessary to account for other greenhouse gases.