Such a move could help the country lower its consumption as well as vulnerability to any possible Western sanctions targeting its fuel imports.
"The gasoline quota for the private motorists will be reduced to 80 liters from the beginning of winter (starting December 22)," IRNA quoted Mohammad Rouyanian, head of Iran's Transportation and Fuel Management Office, as saying.
The current quota is 100 liters per month.
Iran, the world's fifth-largest oil exporter, lacks sufficient refining capacity and imports 40 percent of its gasoline, a burden for its annual budget.
Rouyanian said earlier this week Iran continued to import the fuel despite a reduction in the monthly quota of heavily subsidised gasoline available for motorists.
"We have a $3 billion deficit for importing gasoline until the end of this year (ending March 20, 2010)," he was quoted as saying by the daily Abrar on Monday.
In early November, the same official said Iran needed $3.8 billion (1.8 billion pounds) for gasoline imports until the end of the Iranian year.
The Islamic Republic may face more international sanctions over its nuclear program, which Tehran says is for peaceful electricity generation but which the West suspects is to make atomic bombs.
(Writing by Reza Derakhshi; editing by James Jukwey)
