New Zealanders should not be held to ransom by a trucking industry that has been heavily subsidised by taxpayers for too long, Greens co-leader Jeanette Fitzsimons says.

Truck drivers, furious at a rise in diesel road user charges, plan to clog city centres across the country tomorrow.

The nationwide protest, which organisers have promised will see over 1000 trucks in the centre of Auckland, will run from 7.30am to 9am in a bid to disrupt morning commuters.

Transport Minister Annette King announced the increase in road user charges (RUC) on Monday night and they came into effect on Tuesday -- angering truckies who wanted notice so they could pre-purchase charge vouchers at the old price.

But Ms Fitzsimons today said the trucking industry had been heavily subsidised for years and the price rise, which was small, was warranted.

"I think it's vital that the country does not get held to ransom. That the country just says well, if that's what you're going to do we're going to carry on and ignore you."

She said a 2005 Transport Ministry report showed trucks only paid 56 percent of the costs they caused to the economy whereas rail freight paid 82 percent.

"That distorts the playing field between trucks and rail. That means we have more freight going by big trucks on the road rather than on trains. That's bad for all other road users."

In addition she said road user charges had only been raised once since 1989.

"We know that the costs of maintaining highways have gone up massively during that time. It is time that trucks paid their way."

She encouraged people to train, cycle or walk to work, or even to take the day off.

Meanwhile National's transport spokesman Maurice Williamson today attacked Ms King over what he said was an assurance to the industry last year that she would give them notice of any rise.

He produced emails to industry group the Road Transport Forum suggesting amendments would be made to future legislation to ensure notice was given.

However that amendment never went ahead.

Associate Transport Minister Harry Duynhoven said the idea could not be agreed to because last time there was a rise truckies purchased an extra $17 million in charge vouchers in the two-day period before the rise took effect, defeating the purpose.

ACT leader Rodney Hide told reporters he thought the planned protest tomorrow was "fantastic" and he believed truckies were paying more than their fair share.