OTTAWA - Stephane Dion will deploy Canada's auditor general to backstop his claim that a Liberal carbon tax will be revenue neutral, not the massive tax grab depicted by the Tories.

Revenue neutrality is the central pillar of the Liberal leader's complex plan, to be unveiled later this week, for putting a price on carbon.

Under the plan, the federal treasury would not keep a dime of the roughly $14 billion in revenue the proposed carbon tax would generate. Rather, the money would be shifted back to consumers in the form of offsetting cuts to personal income and corporate taxes.

But Dion is not going to ask Canadians to simply trust him on that.

The plan includes a promise of legislation that would require the independent auditor general to review the tax shift annually and to verify publicly whether it is living up to its advance billing as revenue neutral.

"We will prove this,'' Liberal finance critic John McCallum said in an interview.

"I know politicians aren't always believed, and when we say it's revenue neutral people will be skeptical and they'll refer back to the GST. But we will have the auditor general verify each year it is revenue neutral''.

In the absence of any details, the Tories have been having a field day painting Dion's plan as a massive "tax on everything.'' They've mocked the leader's pledge of revenue neutrality as "weasel words'' that can't be believed given the Liberal party's history of reneging on a onetime promise to scrap the GST.

Jason Kenney, the Tory point man on the issue, has summed up Dion's plan this way: "Hold onto your wallets because he wants to raise your taxes.''

Liberal environment critic David McGuinty believes the Tories' "stupid, cheap, infantile" attacks will backfire as Canadians compare them to Dion's "thoughtful, sincere" approach to the planet's most pressing issue of climate change.

But Dion's proposal is as much an economic plan as an environmental one.

Quite apart from the global warming crisis, Liberals point out that soaring energy prices and finite fossil fuel supplies are causing increasing pain for consumers and mounting economic dislocation in the auto sector and other "smokestack'' industries. The sooner Canadians adjust to those new economic realities, the smaller the negative economic impact and the better positioned Canada will be to take the lead in creating the "green collar'' jobs of the future, they contend.

To that end, Liberals say Dion's plan is aimed at helping wean Canadians off fossil fuels as painlessly as possible. It will include a host of tax measures -- from refundable tax credits to tax incentives and direct tax cuts -- that will be skewed heavily in favour of lower- and middle-income Canadians.

While Dion has promised no additional tax at the gas pumps, his plan will increase the cost of diesel and home heating fuels and electricity. Liberals argue that the NDP and Tory plans to cap the emissions of big polluters would ultimately have the same effect as companies pass the costs down to consumers.

But unlike any other party, Liberals boast that Dion's plan is the only one that will actually help offset those costs.

Insiders say Dion and his inner circle have agonized over details, trying to ensure that no one is unfairly penalized by the carbon tax. Various measures have been built in to protect those who can't afford or can't access alternative energy sources, such as poor, elderly and rural Canadians, or those whose livelihoods are dependent on fossil fuels, such as truck drivers.

Dion's previously announced proposals for reducing poverty by 30 per cent -- and child poverty by 50 per cent _ in five years will also be wrapped into the carbon tax plan. Those proposals include enriching the working income and child tax benefits, extending the child tax credit and raising the Guaranteed Income Supplement for the poorest seniors.

"Every taxpayer will be better off. That's the Dion goal,'' said Liberal MP Garth Turner, who's been helping with the communications strategy for the plan.

McCallum is a bit more circumspect.

"I cannot say to you that no Canadian will be unharmed by this'' he said.

"What I can say is that we've done our very best to ensure that the most vulnerable Canadians will not fall through the cracks and they will have assistance to make the necessary adjustments.

"But the whole planet has to adjust to higher energy prices and costs, and dwindling supply relative to demand for oil, and it's not going to be totally painless for every human being.''