Former British prime minister Tony Blair says the only way to move towards a low carbon economy is to put a price on carbon.
Mr Blair would not specifically buy into the debate about the federal government's carbon tax, saying it was a decision for the Australian people and government.
But, he said, there was a clear move worldwide to shift away from a dependence on carbon.
"Around the world right now people are moving towards a low carbon economy as the future," Mr Blair told reporters in Melbourne.
"The only way you do that in the end is you put some sort of a price on carbon."
Pointing to the experience of introducing a European Union emissions trading scheme, Mr Blair said the policy process was always tough.
"The essential decision that you have to make is are you going over time to move to an economy that is less dependent on carbon.
"If you are, then you usually set the target, around the world people have set targets.
"You inevitably are going to be in a situation therefore where you are going to have to adjust and change your economy."
Prime Minister Julia Gillard and her Labor government have suffered a slide in the polls over the carbon tax issue, but Mr Blair said that was part of the process of making difficult decisions.
"My experience of politics is that if you try to take difficult decisions you always end up causing yourself a certain amount of problems," he told a joint press conference with Ms Gillard.
"But that's what you're there for.
"The question is what's the right decision for the future."
