The Forest Owners Association says longer and heavier loads on trucks will have a major financial benefit for the industry.
The Government has proposed a change in weight and limits for heavy vehicles on specified routes.
The association says transport from the forest to the mill consumes about 25% of the value of a log.
With fewer trips needed if truck size was increased, it says there would be a 20% improvement in productivity and fuel use would fall by nine million litres.
The association says the roads would be safer with less trucks on the road and any damage would also be covered.
It also says carbon emissions would fall by 20,000 tonnes per year.
