Queensland, already the most expensive place in Australia to own a car, will raise vehicle registration fees again on July 1, with the State Opposition accusing the Government of treating motorists as cash cows.

The fees will rise at more than twice the rate of inflation, and come on top of a 3.5 per cent rise in Queensland driver's licence fees due to take effect on July 1, according to the RACQ.

Registration of a four-cylinder car is set to rise by about $12, a six-cylinder car will go up by about $17, while an eight-cylinder car will rise by $23.

It will take registration for four-cylinder cars from $328.90 to $340.40, six-cylinder cars from $492.30 to $509.50 and seven or eight-cylinder cars from $669.80 to $693.25, excluding insurance costs.

Earlier this week before the rise was announced, the RACQ told the ABC Queensland was already the most expensive state in Australia in which to own a car.

No excuse for rego hike: RACQ

The RACQ's Paul Turner said it was an unacceptable impost on drivers.

"A couple of hundred dollars a year more than the average of the other states, so there's no excuse for this," he said.

Opposition transport spokesman Scott Emerson said the LNP government froze car registration costs after they had risen by 30 per cent under the former Labor government.

"We made a very clear promise that we'd freeze family car registration in our first three years in office after those massive hikes that we saw under Labor," he said.

"Labor has now made a decision to slug motorists and increase rego by more than twice the inflation rate.

"We understood the pressures put on motorists and worked hard to be fair to them.

"At the same time as the LNP froze family car registration, it also saw record spending on the Bruce Highway and work beginning for the Toowoomba second range crossing among dozens of other significant road projects across Queensland.

"This is another example of a Government with no plan, no initiatives and making it up as they go."

Money needed to maintain roads: Trad

But Deputy Premier Jackie Trad said the increase was vital for maintaining infrastructure.

"We spend money that we collect through registration on maintaining and building the roads that Queenslanders need," she said.

"No political party went to the last election promising a freeze on registration costs and registration prices in Queensland.

"What we do ensure is that registration fees are pegged to the GIP (Government indexation policy) so they are in step with wage and prices increases, and not beyond that.

"What there was, was a commitment on behalf of Labor to ensure that any increase in registration was pegged to inflation and indexation and we've kept that commitment."