Gasoline prices hit $2 a gallon for the first time since 2015 today as flooding from storm Harvey knocked out almost a quarter of US refineries, while crude prices stabilised following a slump the previous day.

Harvey has battered the US Gulf coast since last Friday, ripping through Texas and Louisiana at the heart of the US petroleum industry.

At least 4.4 million barrels per day of refining capacity was offline, or almost a quarter of total US capacity, based on company reports and Reuters estimates.

Amid fears of a supply squeeze, US gasoline prices today jumped to $2 per gallon for the first time since July 2015.

"The flooding from Hurricane Harvey shut the largest refinery in the US , pushing gasoline prices to a two-year high. In contrast, oil prices retreated," ANZ bank said.

Goldman Sachs said it could take several months before all production could be brought back online.

"While no two natural disasters are similar, the precedent of Rita-Katrina would suggests that 10 per cent of the ... currently offline capacity could remain unavailable for several months," the bank said.

Crude prices stabilised after falling sharply the previous day as the closure of so many US refineries has resulted in a slump in demand for the most important feedstock for the petroleum industry.

US West Texas Intermediate crude futures were trading at $45.96 per barrel, flat from the last day's settlement, when prices fell by 0.8 percent intraday. International Brent crude was at $50.88 a barrel, also virtually flat from its last close, though the contract fell by over 2 percent during the previous session.

Meteorologists said that Harvey could be the worst storm in US history in terms of financial cost.

"The economy's impact, by the time its total destruction is completed, will approach $160 billion," said Joel N. Myers, president and chairman of meteorological firm AccuWeather. Other estimates have put the economic losses from Harvey at under $100 billion.