WASHINGTON—With the federal government hitting its $14.3-billion debt limit, Treasury officials have started a complex fiscal juggling act to postpone the date when the government can no longer pay its bills.

But those accounting tricks, such as tapping two federal employees pension funds for loans, would buy only 11 more weeks for the White House and lawmakers to strike a deal to increase the debt ceiling.

On August 2 the juggling act would be over, Obama administration officials said. That would force the US, for the first time, to begin defaulting on interest payments owed to holders of government securities and trigger a sort of slow-motion partial government shutdown in which Washington would stop paying employees, contractors and beneficiaries of Social Security and other programs.

“It’s a high-wire act,” Rep. Peter Welch, D-Vermont, said of the measures initiated by Treasury Secretary Timothy F. Geithner to postpone the effect of the US reaching its debt limit. “And when he runs out on flexibility and we miss that first payment and the market smashes us, it will be very difficult to put the genie back in the bottle.”

President Barack Obama and congressional Republicans are sharply at odds over major spending cuts to reduce the deficit. Republican leaders and a handful of Democrats have demanded such cuts as a condition for raising the debt ceiling, which Congress has never before failed to increase.

Amid the stalemate, the US reached the ceiling on Monday after the Treasury issued about $72 billion in securities it had auctioned off last week. With the date looming, Geithner already had started employing “extraordinary measures” to continue to allow the government to borrow.

Those steps include suspending investments in federal pension funds and in a currency-exchange rate fund. The moves won’t directly affect people yet, though such maneuvers in the past have led to financial costs to taxpayers.

For example, the Government Accountability Office estimated that a seven-day delay in an auction of two-year securities during a debt-ceiling impasse in 2002 caused the Treasury to pay $19 billion in additional interest
on them each year.

The United States has never defaulted on its payments, and Congress has voted to raise the legal limit on federal borrowing 75 times since 1962. Without the ability to continue to borrow, the Treasury would not have enough money to pay the government’s bills.

Details of what a default would cause are unclear, the Congressional Research Service said in a report last month. Although the government would not be forced to shut down immediately, there could be delays in services and payments from programs such as Social Security and Medicare.

Faced with the potential that Social Security checks would not be issued in 1996, Congress gave the Treasury special authority to issue securities to continue making payments on time until a debt-ceiling stalemate was resolved.

Wall Street analysts believe the US will raise the debt limit by the August 2 deadline rather than risk a default on securities. A default would sharply raise the interest rates investors would demand in the future.

“The likelihood of an actual default, that Treasury misses an interest payment, we would say is very remote,” said Terry Belton, head of fixed income strategy for JPMorgan Securities Inc. “But if it’s not raised by the end of July, the markets would get very jittery then.”

Obama and Republicans remain far apart in their deficit-reduction talks.