The FairFuelUK campaign has taken credit for a series of fuel duty freezes over recent months.
Today, a week ahead of the Budget, the group is presenting a letter to 10 Downing Street calling for a 3p cut.
Backed by such groups as the RAC and the Freight Transport Association, the campaigners said the letter was being presented on behalf of 100 MPs as well as "500,000 supporters and the 32 million road users".
Motoring journalist Quentin Willson accused the Government of being "out of touch" in a post on his blog.
He wrote: "All I'm asking for is to help businesses and families squeeze a tiny bit more out of their thread-bare finances so we can all get through another difficult year. I believe the Government is massively out of touch with the electorate on the fuel issue. They just don't (or won't) understand how many people are struggling out there.
"Having the highest diesel and the second highest petrol duty in the EU slows down business growth and is a tax on the movement of goods and people."
In the letter, campaigners say to Prime Minister David Cameron: "Your clear awareness of the debilitating effects of rising transport costs in a road economy is to be warmly congratulated. But FairFuelUK and the 100 MPs who have been such staunch supporters since 2011 believe there's more to be done.
"We are calling on you to support a 3p duty cut that will continue to bolster the economic recovery. And that recovery so far has been bankrolled by consumer spending and not by industry or manufacturing. "
The letter said 69% of adults polled would like to see the Government reduce the level of fuel duty in the next budget by at least 1p.
It added: "Also, 59% would like a reduction of at least 3p, while 31% want a reduction of 10p. We also know 67% of the population use their cars for essential food shopping and 50% use their cars for work."