Truck drivers are staging a day of action, which will involve driving a convoy into central London.
The protestors are calling for cheaper diesel and for the government to abandon the planned 2p a litre increase in fuel duty planned for October.
They are also lobbying for a fuel duty rebate for heavy goods vehicles.
CPA legal manager David Smith told Construction News plant hire firms are hit with high diesel prices.
He said: "It can have a direct bearing on some of our members' businesses. Some of them have low loaders, which run on Derv, and the percentage price hike in the last year has been phenomenal.
"With the Chancellor indicating that there will be another hike in October; it's going to hit us badly, especially when the fuel in this country is much more than the rest of Europe. UK firms need fuel to run their businesses."