THE UNITED STATES government could effectively shut down overnight if the two main parties in the country fail to agree and pass a new package of budget measures by midnight tonight.

Democrats and Republicans have spent days in talks aimed at agreeing a mutually acceptable package of budget cutbacks, before the current funding arrangements for many federal bodies expire at 12am eastern time (5am Irish time).

Though it has this evening emerged that the two parties have apparently agreed on a target of $38bn for the volume of programmes to be cut, the way in which the target was to be achieved had still yet to be agreed.

The leader of the Democrats’ Senate representation, Harry Reid, said the main sticking point that remained outstanding was the prospective funding of the Planned Parenthood Federation of America, a pro-choice lobby group.

Reid later added that the passage of any bill through Congress would be contingent on whether individual members tried to add controversial ‘riders’, or amendments, to it.

John Boehner, who leads the Republican majority in the House of Representatives, dismissed suggestions that a deal was quite so close and said there was still no substantive agreement between the sides.

While the prospect of a governmental shutdown is not particularly unusual, the fact that the two houses of Congress are not dominated by the same party makes the budgeting process particularly difficult.

Reid’s Democrats hold a majority in the 100-member Senate, while the 435-member House is dominated by Boehner’s Republicans.

If no agreement can be reached, the government will be forced to ‘furlough’ (temporarily lay off) hundreds of thousands of its staff and close public services.

The last such ‘shutdown’ occurred in 1995 when Bill Clinton exercised his presidential veto over the budget measures passed by Congress, where the Republicans enjoyed majorities in both houses.