Australian Trade Minister Simon Crean has slammed new British government duties on air passengers which he says will increase airport taxes by 55 per cent for people flying between the UK and Australia.

Mr Crean has met UK government ministers during a visit to London.

He says a system that determines the amount of tax you pay based on how many miles you fly is outrageous and he told his counterpart Lord Mandelson just that at a meeting overnight.

"Whilst this was originally said to be a duty for environmental purposes, it's now accepted that it's just for revenue raising purposes," he said.

"We've said we understand governments' need to raise revenue, but they shouldn't do it in the discriminatory way in which this tax applies."

In 2011 those wanting to travel to the UK will be charged AU$147 in duty.