SINGAPORE (Reuters) - Oil prices fell in early Asian trading on Tuesday after Goldman Sachs said that prices needed to remain low in coming months to achieve a slowdown in U.S. production growth.

Brent May crude had dropped almost half a dollar to US$57.65 a barrel by 0017 GMT. U.S. May crude was down 39 cents at US$51.76.

The fall came after prices jumped more than 5 per cent on Monday as traders reassessed how quickly Iran might increase exports after a preliminary nuclear deal and anticipated that a months-long rise in U.S. crude inventories may be slowing.

Goldman said in an overnight note that it saw little upside for its US$40 a barrel forecast over the next three months.

"Prices need to remain low in coming months to achieve a sufficient and sustainable slowdown in U.S. production growth," the bank said. "The outlook for U.S. production in 2016 in turn leaves risk to our US$65 per barrel forecast as skewed to the downside."

Goldman said that it expected U.S. crude stocks to peak in April but that inventories would likely rise again by October, putting downward pressure on prices into 2016.

The bank said U.S. output would grow by 700,000 barrels per day year-on-year in 2015, with sequential quarter-on-quarter growth of 170,000 barrels per day in the fourth quarter of 2015, at the current rig count.