LONDON- Iran's budget for next year could be based on an oil price of $40 a barrel, the government's spokesman said in remarks published on an official website on Tuesday, although he added that the budget assumptions were not final yet.

"The revenue sources for the next year's budget are not finalised yet by the government ... Our primary forecast for now is oil at $40 (a barrel)," Ali Rabiei said.

Iran's calendar and fiscal year starts on March 21.

Iran's oil exports have shrunk from more than 2.5 million barrels per day since 2018, when the United States withdrew from Tehran's 2015 nuclear deal with six world powers and reimposed sanctions that have hammered the country's economy.

U.S. President-elect Joe Biden has said he would return to the nuclear pact if Iran resumes compliance.

(Reporting by Bozorgmehr Sharafedin; Editing by Catherine Evans) ((bozorgmehr.sharafedin@thomsonreuters.com; Twitter: @bozorgmehr;))