JAKARTA (REUTERS) - Indonesia is likely to announce a rise in subsidised prices of gasoline and diesel late on Monday, a senior government official told Reuters, a move that will please financial investors and could save Southeast Asia's biggest economy billions of dollars.

President Joko Widodo was poised this month to raise fuel prices by as much as 3,000 rupiah (S$0.32) per litre, but a fall in U.S. crude prices since his Oct. 20 inauguration has eased the pressure to act quickly.

"It seems most likely," said Naryanto Wagimin, acting director general of oil and gas at the energy and mines ministry, when asked if a decision would be announced late on Monday. "Probably the chief economics minister will announce it."

Along with other government ministers and officials, Mr Wagimin said he had been summoned to the chief economics ministry, with a news conference expected to start at 1400 GMT (10 pm Singapore time).

Mr Widodo has been urged by investors to urgently address Indonesia's biggest fiscal problem, a US$23-billion (S$29 million) fuel subsidy bill that is the main driver of the country's twin budget and current account deficits.