Wong today warned that the pledge to offset increases in petrol prices as a result of the carbon trading scheme with a dollar-for-dollar reduction in excise only extends to 2013.

After that, motorists could feel more of the pain of any increase in petrol prices.

However, as she began selling the Government's plan to combat climate change, Senator Wong said the Government was not going to claw back the reductions in fuel excise it had agreed to in the scheme's first three years.

When asked today whether the Government's default position was to scrap the excise offset on petrol when it is reviewed in 2013, unless there were compelling reasons otherwise, Senator Wong replied: “No I, I'm not going to go through the principles of what might occur then but what I was saying was this: it is the adjustment mechanism itself that will be reviewed at that point.”

“It is not the Government's intention to wind the existing offset back but what we will review is what will thereafter would occur, in other words, whether that adjustment would continue.”

Independent Senator Nick Xenophon signalled today he wants to see more help for irrigators and farmers on the frontline of climate change along the Murray in exchange for his vital vote to support an emissions trading scheme in the Senate.

"Those who will be the victims of climate change - those communities on the Murray deserve special consideration,” he told The Australian Online.

"The Government is saying the Murray Darling is in dire straits because of climate change so that needs to be factored in. The burden needs to be shared fairly. For those who feel the sharp end of it we're going to have thousands of irrigators walking off the land and climate change is clearly a factor.”

Senator Xenophon has already held preliminary discussions with Ms Wong, who he said today had the "intellectual smarts" to tackle the complex introduction of a carbon trading scheme.

"It's the most hackneyed phrase in politics - the devil is in the deadline. But it's certainly the case. I acknowledge Australia should be leaders on this, we can't be lecturing the Indonesians about deforestration if we're not taking strong action,” he said.

"But it's how it's done and this green paper is the first step in a significant readjustment to the Australian economy.

"My view is this is going to be one of the most challenging and complex legislation that Australia has seen for a long time. We need to carefully consider the model that is adopted and its implications for the economy.

"But I do agree we should just get on with it.”

The Government's scheme - due to start in July 2010 - was underpinned by the polluter gets paid principle, rather than polluters paying, Greens climate change spokeswoman Christine Milne said.

“The Rudd government is playing politics just like the Howard government,” she said in Canberra.

“This is something that John Howard would be really proud of. It compensates the coal generators.

“The whole point of an emissions trading system is to change the investment signals - and yet instead of that, they want to compensate the coal generators in case there is any change in investment signal.”

“Still we have no mandatory vehicle fuel efficiency, we have no investment in public transport.

“The whole point here is in five years time we are going to be looking at an oil price of $200 or more (a barrel) and no alternatives.

“The Government should have taken responsible leadership and used the fuel excise to roll out public transport around Australia so that low income earners genuinely have an alternative.”

The Australian