The United States appears on the brink of ending a four-decade ban on most exports of crude oil.
The measure is part of a sprawling deal wrapped up by congressional leaders late on Tuesday to keep the US government open through to September.
The $US1.15 trillion ($A1.60 trillion) spending bill, negotiated in secret talks over the last two weeks, would be difficult for President Barack Obama to veto, despite his opposition to ending the oil export ban.
In a partial victory to Obama and other Democrats, the spending bill also includes granting tax incentives to boost wind and solar development, according to politicians involved in the talks. Shares of solar companies rose sharply.
Republican and Democratic politicians will meet separately on Wednesday to discuss the bill and hope to vote on it as soon as Friday.
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Allowing oil exports would be a win for the US oil industry and Republicans, who had argued the ban was a relic of the 1970s Arab oil embargo.
Exploration and production companies, many saddled with billions in debt and struggling to avoid bankruptcy after a 60-per-cent slide in oil prices forced them to halt most new drilling, had viewed exports as a lifeline of sorts.
But with US output now falling as oil prices slump to seven-year lows, traders say foreign buyers may not materialise in a glutted global market.
The bill, posted early on Wednesday morning, allows the US president to stop oil exports for one year if he or she declares a national emergency, or if the administration decides the exports are causing a domestic oil shortage or raising prices.
