President Donald Trump has authorised the broader use of cheaper red-dyed diesel, traditionally reserved for agricultural operations in the United States, as his administration seeks to ease record-high fuel costs.

The White House said the measure could save truckers more than $100 per fill-up.

Under the order, the Treasury Secretary, in consultation with the Department of War, was also directed to defer collection of the federal excise tax on highway diesel through the end of 2026, without interest or penalties, according to a White House fact sheet.

Trump signed an executive order on Monday temporarily allowing truckers and farmers to use red-dyed diesel, which is exempt from highway fuel taxes.

The order also defers related taxes on the fuel through the end of 2026, in a move aimed at reducing fuel costs for consumers and businesses.

The tax-exempt diesel is commonly used in farm equipment, construction machinery, trucks and other off-road vehicles. It is exempt from the 24.4-cent-per-gallon tax imposed on diesel sold for highway transportation.

Using dyed diesel in vehicles on public roads is generally illegal and can attract fines for tax evasion.

However, several US states have relaxed restrictions on its use this year as motorists and businesses grapple with rising fuel prices.

The national average price of diesel in the US surpassed $6 per gallon in September for the first time, as supply disruptions linked to conflicts in Ukraine and Iran drove up transportation costs across the country.