WINNIPEG — Some Liberal MPs are hoping to convince party leader Stephane Dion to make "adjustments" to the controversial national carbon tax proposal, according to the Winnipeg Free Press.

Despite Dion rejecting any criticisms of the scheme in the past, the paper reports that some in the party want Dion to agree to some changes at a planned summer caucus retreat in Winnipeg next week.

Reportedly, they want "to massage" the Green Shift plan to ease the impact on industries hardest hit such as trucking and farming.

"… There are concerns. We don’t deny that," Liberal agriculture critic Wayne Easter, was quoted as saying.

The carbon tax proposal is supposed to be "revenue neutral" — meaning the energy tax would be offset by tax cuts for the public. But trucking companies, for which fuel is becoming their largest expense, would pay a disproportionate amount of the tax.

Dion has insisted the tax would only raise operating ratios marginally and is manageable for the trucking industry.